Transoral approach of anteriorly placed meningioma

Anteriorly placed meningiomas at the level of the foramen magnum are rare, are difficult to diagnose, and present technical problems for a conventional posterior fossa removal.

Previously, the transoral approach garnered interest only from a historical point of view, but with technical progress it has acquired a “second life”. Novel surgical techniques allow for a more radical resection of named tumors, as well as lower morbidity and invasiveness of the surgical procedures, which, in the long term, leads to lower complication rates 1).

Miller and Crockard in 1987 described the successful transoral transclival excision of two such tumors. Cerebrospinal fluid fistula can be avoided by dural repair using a fibrin glue and long term CSF diversion. This modification enables the transoral route to be considered for anteriorly placed intradural lesions 2).


Uchibori et al., in 1990 published a 50-year old woman with a giant parapharyngeal meningioma extending from the intracranial.

The parapharyngeal tumor was biopsied using the transoral approach and a histological section diagnosis suggested meningioma. Thereafter, further examination by magnetic resonance images (MRI) and contrast enhanced CT scans revealed a diffuse meningioma en plaque in the posterior fossaInvasion extended from the clival dura to the right sigmoid sinus. The extracranial extension of a meningioma is very rare but a few cases have been reported. In almost all of the reported cases, a large intracranial meningioma was simultaneously or previously verified by CT scans.

This case was special in that the intracranial mass was not voluminous but showed en plaque extension, and also because the pathway of the extracranial extension through the jugular foramen was clearly visualized by CT and MRI. Obliteration and invasion of the right sigmoid sinus and the internal jugular vein by tumor were also demonstrated 3).


Kondoh et al., presented three cases of foramen magnum meningioma. The first involved a ventral type tumor extending to the second cervical body. Following bilateral mandibulotomy, surgery was performed via the anterior transoral approach and the tumor was totally removed. Nine days postoperatively, she developed meningitis, which was successfully treated with antibiotics. The second patient’s tumor was dorsal type and was deeply embedded in the lateral part of the vermis. The tumor was totally removed via the midline suboccipital approach and she recovered uneventfully, with only slight upper-extremity paresthesia. In the third case, the tumor was ventral type and situated mainly in the clivusCraniotomywas performed by the bilateral suboccipital approach and extended nearly to the jugular tubercle. The tumor, which severely displaced the lower cranial and upper cervical nerves, was totally removed. The postoperative course was lengthy and complicated. Artificial ventilation was required for 2 months, and difficulty in swallowing persisted during long-term follow-up. As illustrated by the second case, dorsal and lateral type foramen magnum meningiomas can usually be removed via the lateral suboccipital approach. In the case of ventral type tumors, the anterior transoral approach entails the risk of infection, as occurred in the first case. They conclude that the lateral suboccipital approach is preferable; craniotomy extending to the jugular tubercle lowers the risk of brainstem damage 4).


Bonkowski et al., published a case of meningioma situated at the anterior rim of the foramen magnum with successful removal via a transoral approach is reported. A new technique of preventing cerebrospinal fluid leakage is described utilizing fascia lata and a bone baffle without any attempt to close the dura, either by primary suture or tissue sealants 5).


In 2001 Imamura et al., reported a 66-year-old female complaining of occipitalgia and numbness of the extremities who had a foramen magnum meningioma. She wastreated via the transoral transclival route with a protective bone baffle, obtained from the iliac bone, securely fixed in the bone window to protect the repaired dura from injury by CSF pulse energy. The patient dont showed CSF leakage or meningitis, and the period of continuous lumbar CSF drainage was only 7 days 6).


An et al., presented two clinical cases in which transoral approach was used to treat ventral meningiomas of the craniovertebral junction. Endoscopic assistance and an original method of anterior atlantooccipital stabilization were used.

Subtotal removal in the first case and complete removal of the tumor in the second case were achieved. In the first case, an unsuccessful attempt of anterior stabilization was made. In the second case, there were no indications for instrumentation (anterior or posterior) as local bone autograft fusion between the condyles and lateral masses of C1 was effectively carried out.

Previously, the transoral approach garnered interest only from a historical point of view, but with technical progress it has acquired a “second life”. Novel surgical techniques allow for a more radical resection of named tumors, as well as lower morbidity and invasiveness of the surgical procedures, which, in the long term, leads to lower complication rates 7).

References

1) , 7)

An S, Chernov 4th, Andreev. Transoral Removal of Ventrally Located Meningiomas of the Craniovertebral Junction. World Neurosurg. 2018 Dec 31. pii: S1878-8750(18)32926-7. doi: 10.1016/j.wneu.2018.12.103. [Epub ahead of print] PubMed PMID: 30605758.
2)

Miller E, Crockard HA. Transoral transclival removal of anteriorly placed meningiomas at the foramen magnum. Neurosurgery. 1987 Jun;20(6):966-8. PubMed PMID: 3614579.
3)

Uchibori M, Odake G, Ueda S, Yasuda N, Hisa I. Parapharyngeal meningioma extending from the intracranial space. Neuroradiology. 1990;32(1):53-5. PubMed PMID: 2333135.
4)

Kondoh T, Tamaki N, Taomoto K, Yasuda M, Matsumoto S. Surgical approaches to foramen magnum meningioma–report of three cases. Neurol Med Chir (Tokyo). 1990 Mar;30(3):163-8. PubMed PMID: 1697042.
5)

Bonkowski JA, Gibson RD, Snape L. Foramen magnum meningioma: transoral resection with a bone baffle to prevent CSF leakage. Case report. J Neurosurg. 1990 Mar;72(3):493-6. PubMed PMID: 2303883.
6)

Imamura J, Ikeyama Y, Tsutida E, Moroi J. Transoral transclival approach for intradural lesions using a protective bone baffle to block cerebrospinal fluid pulse energy–two case reports. Neurol Med Chir (Tokyo). 2001 Apr;41(4):222-6. PubMed PMID: 11381684.

UpToDate: Positron emission tomography for intracranial meningioma

Positron emission tomography for intracranial meningioma

MET PET/CT showed a high sensitivity compared with FDG PET/CT for detection of newly diagnosed WHO grades I and II intracranial meningiomas. Both FDG and MET uptake were found to be useful for evaluating tumor proliferation in meningiomas 1).

Although positron emission tomography has not been routinely used in the diagnostic workup and follow-up of patients with meningiomas, it can be useful in cases of skull base meningiomas that are frequently difficult to visualize by using standard CT and MR imaging techniques 2).

Primary intracranial meningioma is typically reported as having low FDG uptake, because glucose metabolism in meningioma is similar to that of surrounding tissue 3).

There have been a few isolated reports describing the imaging features of metastatic meningioma on FDG-PET imaging. Ghodsian et al., described a moderately hypermetabolic sacral metastatic mass by FDG-PET/CT. This was a Grade III malignant meningioma on histology 4).

Meirelles et al., described a pulmonary meningioma that manifested as a solitary pulmonary nodule and had very high metabolic activity on PET scan. The current case also showed avid uptake of FDG; the SUV was >7 in each pulmonary lesion. The uptake was more avid in the periphery and slightly less in the centre of both lesions, corresponding to the central areas of low density on CT. It was useful to note that there were no other foci of abnormal FDG uptake elsewhere to suggest other metastases. It is reassuring to note that 10 months after the PET/CT with clinical follow-up, the patient remains asymptomatic with no evidence of local or distant spread. The diagnosis of pulmonary metastatic meningioma was confirmed histologically by CT-guided percutaneous biopsy, which has been previously reported 5).


In 2007, Rutten et al., described the combination of CT and MRI as limited in the diagnosis of local skull involvement from adjacent intracranial meningioma. In their study, the authors demonstrated that skull base tumors could be clearly visualised with 18Ftyrosine PET, even after radiation therapy 6) 7).

Meningiomas are also known to have high somatostatin receptor density allowing for the potential use of octreotide brain scintigraphy to help delineate extent of disease. This may be particularly useful in distinguishing residual tumor from postoperative scarring in subtotally resected/recurrent tumors 8).

References

1)

Mitamura K, Yamamoto Y, Norikane T, Hatakeyama T, Okada M, Nishiyama Y. Correlation of (18)F-FDG and (11)C-methionine uptake on PET/CT with Ki-67 immunohistochemistry in newly diagnosed intracranial meningiomas. Ann Nucl Med. 2018 Jul 21. doi: 10.1007/s12149-018-1284-6. [Epub ahead of print] PubMed PMID: 30032455.

2)

Rockhill J, Mrugala M, Chamberlain MC. Intracranial meningiomas: an overview of diagnosis and treatment. Neurosurg Focus. 2007;23(4):E1. Review. PubMed PMID: 17961033.

3)

Kaminski JM, Movsas B, King E, Yang C, Kronz JD, Alli PM, et al. Metastatic meningioma to the lung with multiple pleural metastases. Am J Clin Oncol 2001;24:579–82

4)

Ghodsian M, Obrzut SL, Hyde CC, Watts WJ, Schiepers C. Evaluation of metastatic meningioma with 2-deoxy-2-[18F] fluoro-d-glucose PET/CT. Clin Nucl Med 2005;30:717–20

5)

Brennan C, O’Connor OJ, O’Regan KN, Keohane C, Dineen J, Hinchion J, Sweeney B, Maher MM. Metastatic meningioma: positron emission tomography CT imaging findings. Br J Radiol. 2010 Dec;83(996):e259-62. doi: 10.1259/bjr/11276652. PubMed PMID: 21088084; PubMed Central PMCID: PMC3473618.

6)

Rutten I, Cabay JE, Withofs N, Lemaire C, Aerts J, Baart V, et al.: PET/CT of skull base meningiomas using 2–18F-fluoro-L-tyro-sine: initial report. J Nucl Med 48:720–5, 2007

7)

Conti PS, Cham DK, editors. Singapore: Springer; 2005. PET/CT: a case based approach book.

8)

Klutmann S, Bohuslavizki KH, Brenner W, Behnke A, Tietje N, Kröger S, et al.: Somatostatin receptor scintigraphy in postsurgical follow-up examinations of meningioma. J Nucl Med 39:1913–1917, 1998

Meningioma asintomático

Meningioma asintomático

El meningioma intracraneal asintomático es un tumor benigno; sin embargo, casi dos tercios de los pacientes experimentan crecimiento tumoral y un tercio de los pacientes no tratados finalmente requieren intervención neuroquirúrgica 1).
En la serie de Jadid et al., el crecimiento tumoral a largo plazo de los meningiomas asintomáticos detectados incidentalmente parece ser mucho más alto de lo esperado. Esta información debe tenerse en cuenta cuando se habla de cirugía, ya que la indicación para la cirugía puede ser más fuerte que la mencionada anteriormente, especialmente para pacientes más jóvenes con tumores que se pueden abordar con un bajo riesgo 2).
Para Yoneoka et al., el seguimiento clínico-radiológico es especialmente aconsejable en pacientes jóvenes y con un tumor grande 3).
Para el meningioma en el anciano asintomático, Niiro et al., recomienda realizar un seguimiento clínico y de imágen. Las características de imagen mencionadas en su artículo pueden contribuir a la predicción del crecimiento tumoral 4).
Hashimoto et al., observaron que el meningioma de la base de cráneo incidental no tiende a crecer, lo que es diferente de los tumores que no son de base del cráneo. Incluso cuando el meningioma de la base de cráneo crece, la tasa de crecimiento es significativamente menor que la de los tumores que no son de la base del cráneo. La misma conclusión con respecto al comportamiento biológico se confirmó en casos sintomáticos basados ​​en análisis MIB-1. Estos hallazgos pueden afectar la comprensión de la historia natural del meningioma intracraneal incidental, así como las estrategias para el tratamiento y tratamiento del meningioma de la base de cráneo y los meningiomas sintomáticos 5).
En el estudio de Karatsu se realizó un seguimiento durante más de un año a 63 pacientes con meningioma asintomático, observando crecimiento en la tercera parte de los mismos. Los que muestran crecimiento son hiperintensos en las imágenes de T2 de resonancia magnética con mayor frecuencia que los estacionarios, mientras que éstos son isointensos o hipointensos y están calcificados en una clara mayor proporción. No se observó diferencia significativa en la edad de los pacientes en función del crecimiento del tumor. La menor tendencia al crecimiento de los meningiomas calcificados también ha sido observada por otros autores
En una serie de 45 pacientes con meningioma asintomático, Olivero et al comprobaron crecimiento únicamente en el 22%, a una velocidad lenta variable, en torno a 0’24 cm de diámetro por año. También se ha observado que los meningiomas asintomáticos se localizan con mayor frecuencia en el hemisferio cerebral derecho. Como es obvio, cuando se decide no intervenir se debe realizar un seguimiento clínico y neurorradiológico del paciente 6).
1)

Kim KH, Kang SJ, Choi JW, Kong DS, Seol HJ, Nam DH, Lee JI. Clinical and radiological outcomes of proactive Gamma Knife surgery for asymptomatic meningiomas compared with the natural course without intervention. J Neurosurg. 2018 May 18:1-10. doi: 10.3171/2017.12.JNS171943. [Epub ahead of print] PubMed PMID: 29775154.
2)

Jadid KD, Feychting M, Höijer J, Hylin S, Kihlström L, Mathiesen T. Long-term follow-up of incidentally discovered meningiomas. Acta Neurochir (Wien). 2015 Feb;157(2):225-30. doi: 10.1007/s00701-014-2306-3. Epub 2014 Dec 14. PubMed PMID: 25503298.
3)

Yoneoka Y, Fujii Y, Tanaka R. Growth of incidental meningiomas. Acta Neurochir (Wien). 2000;142(5):507-11. PubMed PMID: 10898357.
4)

Niiro M, Yatsushiro K, Nakamura K, Kawahara Y, Kuratsu J. Historia natural de pacientes ancianos con meningiomas asintomáticos. J Neurol Neurosurg Psychiatry. 2000 ene; 68 (1): 25-8. PubMed PMID: 10601396; PubMed Central PMCID: PMC1760589.
5)

Hashimoto N, Rabo CS, Okita Y, Kinoshita M, Kagawa N, Fujimoto Y, Morii E, Kishima H, Maruno M, Kato A, Yoshimine T. Slower growth of skull base meningiomas compared with non-skull base meningiomas based on volumetric and biological studies. J Neurosurg. 2012 Mar;116(3):574-80. doi: 10.3171/2011.11.JNS11999. Epub 2011 Dec 16. PubMed PMID: 22175721.

Update: Asymptomatic Meningioma

Asymptomatic Meningioma

Asymptomatic intracranial meningioma is a benign disease; however, nearly two-thirds of patients experience tumor growth and one-third of untreated patients eventually require neurosurgical interventions during watchful waiting 1).

In the series of Jadid et al., long-term tumour growth of incidentally detected asymptomatic meningiomas appeared to be much higher than expected. This information needs to be considered when discussing surgery, since the indication for surgery may be stronger than previously stated, especially for younger patients with tumours that can be reached at low risk 2).

Niiro et al., stated that in elderly patients with asymptomatic meningiomas, careful clinical follow up with imaging studies is important. The imaging features mentioned in his article may contribute to prediction of tumour growth 3).

For Yoneoka et al., clinical and radiological observations would be advisable for these patients (especially young patients and patients with a large tumour), in view of the presence of rapidly growing tumours in some of the patients 4).

Hashimoto et al., observed that Skull base incidental meningiomas (IDM) tend not to grow, which is different from non-skull base tumors. Even when IDMs grow, the rate of growth is significantly lower than that of non-skull base tumors. The same conclusion with regard to biological behavior was confirmed in symptomatic cases based on MIB-1 index analyses. This findings may impact the understanding of the incidental intracranial meningioma natural history, as well as strategies for management and treatment of IDMs and symptomatic meningiomas 5).

Asymptomatic meningioma treatment

Asymptomatic meningioma case series

References

1)

Kim KH, Kang SJ, Choi JW, Kong DS, Seol HJ, Nam DH, Lee JI. Clinical and radiological outcomes of proactive Gamma Knife surgery for asymptomatic meningiomas compared with the natural course without intervention. J Neurosurg. 2018 May 18:1-10. doi: 10.3171/2017.12.JNS171943. [Epub ahead of print] PubMed PMID: 29775154.

2)

Jadid KD, Feychting M, Höijer J, Hylin S, Kihlström L, Mathiesen T. Long-term follow-up of incidentally discovered meningiomas. Acta Neurochir (Wien). 2015 Feb;157(2):225-30. doi: 10.1007/s00701-014-2306-3. Epub 2014 Dec 14. PubMed PMID: 25503298.

3)

Niiro M, Yatsushiro K, Nakamura K, Kawahara Y, Kuratsu J. Natural history of elderly patients with asymptomatic meningiomas. J Neurol Neurosurg Psychiatry. 2000 Jan;68(1):25-8. PubMed PMID: 10601396; PubMed Central PMCID: PMC1760589.

4)

Yoneoka Y, Fujii Y, Tanaka R. Growth of incidental meningiomas. Acta Neurochir (Wien). 2000;142(5):507-11. PubMed PMID: 10898357.

5)

Hashimoto N, Rabo CS, Okita Y, Kinoshita M, Kagawa N, Fujimoto Y, Morii E, Kishima H, Maruno M, Kato A, Yoshimine T. Slower growth of skull base meningiomas compared with non-skull base meningiomas based on volumetric and biological studies. J Neurosurg. 2012 Mar;116(3):574-80. doi: 10.3171/2011.11.JNS11999. Epub 2011 Dec 16. PubMed PMID: 22175721.

Invasive meningioma

Invasive meningioma

Invasive intracranial meningioma is a common neoplasm of central nervous system, which can infiltrate adjacent tissues (dura materarachnoid membrane, vascular space and skull) without atypical hyperplasia 1) 2)
In general, the pathological nature of meningioma determines its association with the brain parenchyma, which is that benign meningioma is usually compressive to the brain parenchyma due to its expansive growth, and malignant meningioma is invasive into the neighboring brain parenchyma due to its intrusive growth 3) 4). However, clinical observations have indicated that there is a sub-group of benign meningioma displaying a malignant growth pattern, that is, invasion into the neighboring brain tissue 5) 6) 7) 8) 9).
According to the experience gained in 19 cases, it was observed that there were certain features shared by these invasive benign meningiomas. The peak age of onset was ~50 years; the main manifestation was mild focal neurological deficits, which included dysphasia, and decreased sensation and muscle power of the contralateral limb. The MRI findings usually had the following characteristics: The lesions were located at the convexity of the cerebral hemisphere involving the central lobe, with an extensive base at the dural matter and evident ‘tail sign’; there was a minimal boundary between the tumor and the neighboring brain cortex; finally, and probably most importantly, the apex of tumor often enwrapped the normal brain tissue and associated vessels.
Due to the malignant growth, it was challenging to completely remove this benign meningioma while ensuring that neurological function remained intact. Resection of the earliest 4 cases was performed according to the traditional extra-capsular strategy, which was to coagulate and divide the tumor base first, and then continue the dissection along the interface between the tumor and brain parenchyma. This approach inevitably damaged the vessels transiting from and into the tumor. The observation that all 4 cases had permanent neurological deficits confirmed the disadvantage associated with this surgical strategy. Following careful analysis of the surgical outcomes, the resection method was modified by combining intra- and extra-capsular approaches. The first step was the same as the classical method, which was to coagulate and divide the tumor base. Afterwards, intra-capsular extirpation of the central part of the tumor was performed. Care was taken not to damage the transit vessels when approaching the tumor-brain interface. The enucleation of the central part of the tumor created a working space, which greatly facilitated the identification of the transit vessels. After this, the tumor was separated from brain parenchyma along the sub-arachnoid membrane. The use of a sponge during this dissection process was important. Finally, it was critical to separate the enwrapped brain cortex and associated vessels from the invading ‘cauliflower-like’ nodules of the meningioma. It is recommended that no efforts are spared in this process, since the enwrapped brain tissue may have retained its ability to function. The observation that there was only 1 case with mild neurological impairment post-operatively in the later 15 cases confirms the advantage of the modified strategy.
In summary, the present study further revealed the clinical features of the invasive benign meningioma and indicated the advantage of combined intra-extra capsular strategy for the surgical resection 10).


Identification of risk factors for perioperative epilepsy remains crucial in the care of patients with meningioma. Moreover, associations of brain invasion with clinical and radiological variables have been largely unexplored. Brain invasion was identified as a new and strong predictor for preoperative, but not postoperative, seizures. Although also associated with increased peritumoral edema, seizures in patients with invasive meningioma might be facilitated substantially by cortical invasion itself. Consideration of seizures in consultations between the neurosurgeon and neuropathologist can improve the microscopic detection of brain invasion 11).

Case series

2018

Hess et al., hypothesized that invasion of the cortex and subsequent increased edema facilitate seizures, and they compared radiological data and perioperative seizures in patients with brain-invasive meningioma or noninvasive meningioma.
Correlations of brain invasion with tumor and edema volumes and preoperative and postoperative seizures were analyzed in univariate and multivariate analyses.
Totals of 108 (61%) females and 68 (39%) males with a median age of 60 years and harboring totals of 92 (52%) grade I, 79 (45%) grade II, and 5 (3%) grade III tumors were included. Brain invasion was found in 38 (22%) patients and was absent in 138 (78%) patients. The tumors were located at the convexity in 72 (41%) patients, at the falx cerebri in 26 (15%), at the skull base in 69 (39%), in the posterior fossa in 7 (4%), and in the ventricle in 2 (1%); the median tumor and edema volumes were 13.73 cm3 (range 0.81-162.22 cm3) and 1.38 cm3 (range 0.00-355.80 cm3), respectively. As expected, edema volume increased with rising tumor volume (p < 0.001). Brain invasion was independent of tumor volume (p = 0.176) but strongly correlated with edema volume (p < 0.001). The mean edema volume in noninvasive tumors was 33.0 cm3, but in invasive tumors, it was 130.7 cm3 (p = 0.008). The frequency of preoperative seizures was independent of the patients’ age, sex, and tumor location; however, the frequency was 32% (n = 12) in patients with invasive meningioma and 15% (n = 21) in those with noninvasive meningioma (p = 0.033). In contrast, the probability of detecting brain invasion microscopically was increased more than 2-fold in patients with a history of preoperative seizures (OR 2.57, 95% CI 1.13-5.88; p = 0.025). In univariate analyses, the rate of preoperative seizures correlated slightly with tumor volume (p = 0.049) but strongly with edema volume (p = 0.014), whereas seizure semiology was found to be independent of brain invasion (p = 0.211). In multivariate analyses adjusted for age, sex, tumor location, tumor and edema volumes, and WHO grade, rising tumor volume (OR 1.02, 95% CI 1.00-1.03; p = 0.042) and especially brain invasion (OR 5.26, 95% CI 1.52-18.15; p = 0.009) were identified as independent predictors of preoperative seizures. Nine (5%) patients developed new seizures within a median follow-up time of 15 months after surgery. Development of postoperative epilepsy was independent of all clinical variables, including Simpson grade (p = 0.133), tumor location (p = 0.936), brain invasion (p = 0.408), and preoperative edema volume (p = 0.081), but was correlated with increasing preoperative tumor volume (p = 0.004). Postoperative seizure-free rates were similar among patients with invasive and those with noninvasive meningioma (p = 0.372).
Brain invasion was identified as a new and strong predictor for preoperative, but not postoperative, seizures. Although also associated with increased peritumoral edema, seizures in patients with invasive meningioma might be facilitated substantially by cortical invasion itself. Consideration of seizures in consultations between the neurosurgeon and neuropathologist can improve the microscopic detection of brain invasion12).

2017

From February 2014 to February 2016, 59 patients with invasive meningioma were enrolled in a study. Invasive meningioma was confirmed in all patients by operation. Information about clinical manifestations, pathological features, preoperative imaging and surgical treatment were collected and analyzed. After surgery, pathological specimens were collected, and cases were confirmed as invasive meningioma by pathological examination. The course of disease ranged from 15 days to 7 years (average, 13.2 months). We used World Health Organization (WHO) criteria for classification of meningioma in the nervous system tumors as our reference. Symptoms were as follows: Intracranial hypertension (29 cases), cranial nerve dysfunction (10 cases), epilepsy (11 cases) and other symptoms (9 cases). We had 56 cases of WHO grade I; 6 cases of WHO grade II and 7 cases of WHO grade III. Surgical removal was: Simpson grade I (56 cases), Simpson grade II (2 cases), Simpson grade III and above (56 cases). We used before surgery imaging data to formulate our surgical plan. In general, during surgeries we did not proceed to complete resection, because in the majority of cases, some key structures were invaded and meningioma was very deep and any attempt for total resection could easily lead to significant damage to these structures 13).

1995

A study was undertaken to investigate the correlation between histological invasiveness and proliferating potential and clinical recurrence in meningioma. In 39 meningiomas, the histological findings at the tumour-brain interface zone were classified into 3 types, consisting of 29 cases of non-invasion (NON). 7 cases of nodular invasion (NOD), and 3 cases of intermingled invasion (INT). Proliferating cell nuclear antigen (PCNA) and argyrophilic nucleolar organizer region (AgNOR) indices were studied. PCNA indices (mean +/- standard error) of NON, NOD. and INT were 1.7 +/- 0.1%, 5.2 +/- 0.5%, and 7.5 +/- 0.7%. respectively, and the AgNOR indices (dot number/nucleus) were 1.50 +/- 0.03, 2.00 +/- 0.04, and 2.22 +/- 0.07, respectively. Significant differences were found among the three types in both parameters. Clinically, tumour recurrence was observed in 1/29 NON, 4/7 NOD, and 2/2 INT cases, indicating a higher incidence of recurrence in invasive meningiomas (NOD plus INT). Four of 32 patients who underwent gross total removal of the tumours showed recurrence, and all of these four tumours were invasive meningiomas. The results of the present study showed that tumour invasiveness as measured by PCNA + AgNOR indices correlated well with high proliferative potential and clinical recurrence 14).
1)

Gelabert-González M, Serramito-García R. Intracranial meningiomas: I. Epidemiology, aetiology, pathogenesis and prognostic factors. Rev Neurol. 2011;53:165–172.
2)

Bondy M, Ligon BL. Epidemiology and etiology of intracranial meningiomas: a review. J Neurooncol. 1996;29:197–205. doi: 10.1007/BF00165649.
3)

Riemenschneider MJ, Perry A, Reifenberger G. Histological classification and molecular genetics of meningiomas. Lancet Neurol. 2006;5:1045–1054. doi: 10.1016/S1474-4422(06)70625-1.
4)

Modha A, Gutin PH. Diagnosis and treatment of atypical and anaplastic meningiomas: A review. Neurosurgery. 2005;57:538–550. doi: 10.1227/01.NEU.0000170980.47582.A5.
5)

Trembath D, Miller CR, Perry A. Gray zones in brain tumor classification: Evolving concepts. Adv Anat Pathol. 2008;15:287–297. doi: 10.1097/PAP.0b013e3181836a03.
6)

Gay E, Lages E, Ramus C, Guttin A, El Atifi M, Dupré I, Bouamrani A, Salon C, Ratel D, Wion D, et al. The heterogeneity of meningioma revealed by multiparameter analysis: Infiltrative and non-infiltrative clinical phenotypes. Int J Oncol. 2011;38:1287–1297.
7)

Fritz J, Roser F, Tatagiba M, Bornemann A. The basement membrane at the tumour-brain interface of brain-invasive grade I meningiomas. Neuropathol Appl Neurobiol. 2005;31:339–342. doi: 10.1111/j.1365-2990.2005.00661.x.
8)

Utsuki S, Oka H, Sato Y, Kawano N, Tsuchiya B, Kobayashi I, Fujii K. Invasive meningioma is associated with a low expression of E-cadherin and beta-catenin. Clin Neuropathol. 2005;24:8–12.
9)

Suwa T, Kawano N, Oka H, Ito H, Kameya T. Invasive meningioma: A tumour with high proliferating and ‘recurrence’ potential. Acta Neurochir (Wien) 1995;136:127–131. doi: 10.1007/BF01410613.
10)

Lin Q, Ling F, Xu G. Invasive benign meningioma: Clinical characteristics, surgical strategies and outcomes from a single neurosurgical institute. Exp Ther Med. 2016 Jun;11(6):2537-2540. Epub 2016 Apr 4. PubMed PMID: 27284345; PubMed Central PMCID: PMC4887900.
11) , 12)

Hess K, Spille DC, Adeli A, Sporns PB, Brokinkel C, Grauer O, Mawrin C, Stummer W, Paulus W, Brokinkel B. Brain invasion and the risk of seizures in patients with meningioma. J Neurosurg. 2018 Apr 27:1-8. doi: 10.3171/2017.11.JNS172265. [Epub ahead of print] PubMed PMID: 29701550.
13)

Hou W, Ma Y, Xing H, Yin Y. Imaging characteristics and surgical treatment of invasive meningioma. Oncol Lett. 2017 May;13(5):2965-2970. doi: 10.3892/ol.2017.5833. Epub 2017 Mar 9. PubMed PMID: 28521402; PubMed Central PMCID: PMC5431211.
14)

Suwa T, Kawano N, Oka H, Ito H, Kameya T. Invasive meningioma: a tumour with high proliferating and “recurrence” potential. Acta Neurochir (Wien). 1995;136(3-4):127-31. PubMed PMID: 8748841.

Update: Skull base meningioma

Skull base meningioma

Epidemiology

As with intracranial meningiomas in other regions, skull base meningiomas demonstrate a femalepredominance, with a female-to-male ratio as high as 3:1.
Approximately 15% of meningiomas grow along the sphenoid ridge, with 10% developing in the posterior cranial fossa and 5% in the olfactory groove.
Meningiomas of the floor of the middle fossa are uncommon and tend to grow quite large before diagnosis.
Skull-base meningiomas are characterized by other recurrent mutations, including AKT1, SMOKLF4TRAF7 and POLR2A.

Classification

Treatment

Efforts to achieve a radical resection with dural margin are not suitable in many cases of skull base meningiomas, because of the neurovascular structures around the tumors.
Gamma knife radiosurgery (GKRS) is well established in the management of inaccessible, recurrent, or residual benign skull base meningiomas. Most series report clinical outcome parameters and complications in the short intermediate period after radiosurgery.
GKRS offers a highly durable rate of tumor control for World Health Organization grade 1 meningioma, with an acceptably low incidence of neurological deficits. The Karnofsky Performance Scale at the time of radiosurgery serves as a reliable long-term predictor of overall outcome 1).

Outcome

Peritumoral edema (PTE) in skull base meningiomas correlates to the absence of an arachnoid plane and difference in outcome.
A subset of benign (WHO grade I) skull base meningiomas show early progression/recurrence (P/R) in the first years after surgical resection.
Ko et al. retrospectively investigated the preoperative CT and MR imaging features for the prediction of P/R in skull base meningiomas, with emphasis on quantitative ADC values. Only patients had postoperative MRI follow-ups for more than 1 year (at least every 6 months) were included. From October 2006 to December 2015, total 73 patients diagnosed with benign (WHO grade I) skull base meningiomas were included (median follow-up time 41 months), and 17 (23.3%) patients had P/R (median time to P/R 28 months). Skull base meningiomas with spheno-orbital location, adjacent bone invasion, high DWI, and lower ADC value/ratio were significantly associated with P/R (P < 0.05). The cut-off points of ADC value and ADC ratio for prediction of P/R are 0.83 × 10- 3 mm2/s and 1.09 respectively, with excellent area under curve (AUC) values (0.86 and 0.91) (P < 0.05). In multivariate logistic regression, low ADC values (< 0.83 × 10- 3 mm2/s) and adjacent bone invasion are high-risk factors of P/R (P < 0.05), with odds ratios of 31.53 and 17.59 respectively. The preoperative CT and MRI features for prediction of P/R offered clinically vital information for the planning of treatment in skull base meningiomas 2).

Case series

2018

From a prospectively maintained database of 2022 meningioma patients who underwent Leksell stereotactic radiosurgery (SRS) during a 30-year interval, we found 98 patients with petroclival, 242 with cavernous sinus, and 55 patients with cerebellopontine angle meningiomas. Primary radiosurgery was performed in 245 patients. Patients included in this report had at least one CN deficit at the time of initial presentation and a minimum of 12 month follow up. Median age at the time of SRS was 58 years. Median follow up was 58 months (range 12-300 months), Median tumor volume treated with SRS was 5.9 cm3 (range 0.5-37.5 cm3), and median margin dose was 13 Gy (range 9-20Gy).
Tumor control was achieved in 229 patients (93.5%) at a median follow up of 58 months. Progression free survival rate (PFS) after SRS was 98.7% at 1 year, 96.4% at 3 years, 93.7% at 5 years, and 86.4% at 10 years Overall, 114 of the 245 patients (46.5%) reported improvement of CN function. Patients with CP angle meningiomas demonstrated lower rates of CN improvement compared to petroclival and cavernous sinus meningioma patients. Deterioration of CN function after SRS developed in 24 patients (10%). The rate of deterioration was 2.8% at 1 year, 5.2% at 3 years, and 8% at 10 years.
Primary SRS provides effective tumor control and favorable rate of improvement of preexisting CN deficit 3).

2011

Fourty-six patients harboring a skull base meningioma underwent an endoscope-assisted microsurgical resection. In 30 patients (65%), tumor parts which could not be visualized under the microscope were detected with the endoscope. In 26 patients (56%), these tumor remnants were removed under endoscopic view. Gross total resection was achieved in 35 patients (76%) and near-total resection in 11 (24%). There was no surgical mortality. The major complication was new cranial nerve deficit. The application of endoscopes was most useful in the small supraorbital craniotomies to look under the ipsilateral optic nerve and internal carotid artery as well as to visualize the diaphragm sellae and olfactory groove. In the retrosigmoid craniotomies, the endoscope was beneficial to inspect the internal auditory canal, to look into Meckel’s cave, or to inspect areas hidden behind the jugular tubercle and tentorial edge. There was no obvious complication related to the application of the endoscope. Endoscope assistance is particularly of value when skull base meningiomas are to be removed via small craniotomies to inspect blind corners which cannot be visualized in a straight line with the microscope. In addition, there is a benefit of using endoscopes with various angles of view in standard craniotomies and skull base approaches to look around bony and dural corners or to look behind neurovascular structures, by which the amount of skull base drilling and retraction to expose the tumor can be reduced 4).
1)

Cohen-Inbar O, Lee CC, Schlesinger D, Xu Z, Sheehan JP. Long-Term Results of Stereotactic Radiosurgery for Skull Base Meningiomas. Neurosurgery. 2016 Jul;79(1):58-68. doi: 10.1227/NEU.0000000000001045. PubMed PMID: 26421592.
2)

Ko CC, Lim SW, Chen TY, Chen JH, Li CF, Shiue YL. Prediction of progression in skull base meningiomas: additional benefits of apparent diffusion coefficient value. J Neurooncol. 2018 Jan 20. doi: 10.1007/s11060-018-2769-9. [Epub ahead of print] PubMed PMID: 29353434.
3)

Faramand A, Kano H, Niranjan A, Johnson SA, Hassib M, Park KJ, Arai Y, Flickinger JC, Lunsford LD. Cranial nerve outcomes after primary stereotactic radiosurgery for symptomatic skull base meningiomas. J Neurooncol. 2018 Apr 24. doi: 10.1007/s11060-018-2866-9. [Epub ahead of print] PubMed PMID: 29691775.
4)

Schroeder HW, Hickmann AK, Baldauf J. Endoscope-assisted microsurgical resection of skull base meningiomas. Neurosurg Rev. 2011 Oct;34(4):441-55. doi: 10.1007/s10143-011-0322-9. Epub 2011 May 26. PubMed PMID: 21614425.

Update: Falcotentorial meningioma treatment

Falcotentorial meningioma treatment

The primary aim of surgical treatment for falcotentorial meningiomas is gross total excision. The vital surrounding brain structures make this a complex task.
Several surgical approaches have been described to treat falcotentorial meningiomas. These include infratentorial supracerebellar approachsuboccipital approachoccipital transtentorial approach, and combined supratentorial and infratentorial approaches 1) 2) 3).
There are two main issues in treating falcotentorial meningiomas. One is selecting the surgical approach, which includes design of the bone flap. The other main issue is whether main venous structures will be sacrificed for a radical tumor resection.
In all of the cases, Hong et al. tried to make an adequately sized bone flap, even when the tumor was quite large. Some authors have insisted on performing wide craniotomies for large falcotentorial meningiomas 4).
Quiñones-Hinojosa, et al. 5) described a bilateral occipital transtentorial/transfalcine approach for large falcotentorial meningiomas. They ligated and cut the transverse sinus after checking the patency of the occluded sinus, and used permanent aneurysmal clips to ligate the vein of Galenwhen the straight sinus was occluded. The area above and below the tentorium can provide wide exposure and reduce occipital lobe retraction during prolonged operation times. Moreover, this approach may allow surgeons some form of intraoperative flexibility in terms of their surgical plan.
Hong et al. do not suggest routine application of wide craniotomies, such as the combined supratentorial and infratentorial approach. This is because wide craniotomies may increase the total amount of bleeding, prolong the operation time, and increase the risk of cerebral cortex injury. Moreover, it is possible to completely remove huge falcotentorial meningiomas without neurological deficit via relatively small craniotomies.
A catheter for CSF drainage was inserted into the ventricle or cisternal space through the safest area in each patient. They also designed small craniotomies through which the possible access area covered the entire tumor territory. Thus, if a CSF drain is possible, then appropriately designed small craniotomies are sufficient to achieve complete tumor resection without cortex injury 6).
There are some reports that have described usage of ligation and sectioning of the transverse sinus with or without reanastomosis 7) 8).
Although many authors have reported safe ligation of the transverse-sigmoid sinus, some complications have been described 9) 10).
Every venous structure should be preserved even if they seem to lack significant function. This will help prevent complications associated with delayed lobar parenchymal hemorrhage that can be attributed to venous infarction.
In conclusion, surgical approaches should be tailored to each patient according to the origin and direction of tumor growth, feeding arteries, and the surrounding venous drainage system.
Hong et al. found that a relatively small craniotomy was sufficient to completely remove each tumor. Moreover, they found that the most important factors for avoiding surgical complications were to preserve vital deep neurovascular structures, as well as flow through the venous sinuses.
The results showed that falcotentorial meningiomas could be cured via single-stage operations without complications by applying careful perioperative planning and a delicate microsurgical technique 11).

Videos



In this operative video, the authors demonstrate an illustrative step-by-step technique for endoscopic-assisted microsurgical resection of a falcotentorial meningioma using the posterior interhemispheric retrocallosal transfalcine approach for a superiorly positioned falcotentorial meningioma. The surgical nuances are discussed, including the surgical anatomy, gravity-assisted interhemispheric approach in the lateral position, retrocallosal dissection, transfalcine exposure, tumor removal, and preservation of the vein of Galen complex. In summary, the posterior interhemispheric retrocallosal transfalcine approach is a useful surgical strategy for select superiorly positioned falcotentorial meningiomas.

Case series

2009

From 2001 to 2005, 9 patients underwent operation for meningiomas arising from the falcotentorial junction, with some extending to and/or invading the torcula. All patients were assessed preoperatively with magnetic resonance neuroimaging and cerebral angiography. Furthermore, preoperative embolization was attempted in all cases. A supratentorial/infratentorial torcular craniotomy technique was used in all but 1 of these cases.
The average dimensions of the falcotentorial meningiomas were 5.1 x 4.4 x 4.2 cm. The angiograms revealed that these tumors were fed by branches of the internal carotid artery, choroidal arteries, branches of the meningohypophyseal trunk, and branches of the posterior cerebral artery. Preoperative embolization was achieved in only 2 patients. Five patients had gross total resection (Simpson grade 1), and 4 had subtotal resection (Simpson grade 4). Two of the tumors (22%) recurred during a mean follow-up period of 49 months (range, 17-88 months). The most common complication after surgery was cortical blindness, but all postoperative visual deficits had fully recovered at the last follow-up evaluation within several months.
An excellent outcome can be expected with detailed preoperative neuroimaging and knowledge of the nuances of the surgical technique that we describe in detail in the article 12).

2006

Goto et al. evaluated their surgical experience over 20 years with 14 treated falcotentorial meningiomas.
In the past 20 years, 14 patients with falcotentorial junction meningiomas were surgically treated. There were seven men and seven women, whose ages ranged from 34 to 79 years. On the basis of neuroimaging studies, the authors analyzed the influence of the anatomical relationship of the tumor to the vein of Galen, patency of the vein of Galen, tumor size, and the signal intensities on the magnetic resonance images to determine possible difficulties that might be encountered during surgery and to prognosticate the outcome of surgery. Depending on the relationship with the vein of Galen, tumors were labeled as either a superior or an inferior type. All tumors were resected via an occipital transtentorial approach. The surgical outcome in eight patients was excellent; in the remaining six patients, it was fair. Of the prognostic factors, tumor location especially seemed to be the most important (p < 0.01, Fisher exact test). The outcome associated with the inferior type of tumor was significantly less optimal probably due to the relationship to the deep veins and the brainstem. In this series, the occlusion of deep veins did not significantly influence outcome.
Classification of the tumor location by preoperative neuroimaging studies can be helpful in estimating the surgical difficulty that might be encountered in treating the falcotentorial junction meningioma 13).

2003

Meningiomas arising from the falcotentorial junction are rare. As a result, their clinical presentation and surgical management are not well described. During the past 3 years, the authors have treated six patients with falcotentorial meningiomas.
Most patients presented with symptoms related to raised intracranial pressure, including headaches, papilledema, and visual and gait disturbances. Magnetic resonance imaging revealed a smooth, oval, or round mass, which was typically homogeneously enhancing. Angiography was useful in evaluating arterial supply for embolization, when possible, and determining the status of venous collateral supply and sinus patency. The authors detail the surgical technique used in all six patients. Postoperatively, patients experienced transient cortical blindness, which in all cases spontaneously resolved during the course of several days to weeks. They provide a comprehensive description of the presentation and surgical management of falcotentorial meningiomas.
An excellent outcome can be expected when surgery is predicated on detailed preoperative neuroimaging and knowledge of the nuances of the surgical technique 14).

2001

Okami et al. present four surgical cases. An occipital transtentorial approach was used in three cases, and a combined midline occipital and suboccipital approach in one case. Total tumour excision was impossible in two cases because of engulfing deep venous structures including the great vein of Galen. Postoperative Gamma knife radiosurgery was performed in these two cases. On the other hand, a posteriorly located tumour was relatively easy to remove, and macroscopic total removal was accomplished. In conclusion, precise microvascular anatomical knowledge is indispensable to satisfactorily excise meningiomas in the falcotentorial area without significant morbidity 15).

1995

Asari et al. describe the clinical features, neuroimaging studies, and results of surgical treatment of meningiomas of the falcotentorial junction and clarify the characteristics of this lesion based on a review of the literature and seven patients treated at their institution. The most common symptoms resulted from intracranial hypertension. Upward-gaze palsy appeared in only one patient. Computerized tomography (CT) showed no specific findings, but there was no evidence of edema around the tumor. Magnetic resonance (MR) imaging revealed a round, smooth-bordered mass with a peritumoral rim, without edema, and showing marked contrast enhancement. The multiplanar capability of MR imaging delineated the relationship between the tumor and adjacent structures better than did CT. Detailed knowledge of the vascular structures, especially evidence of occlusion of the galenic venous system and the development of collateral venous channels, is critical for successful surgery; stereoscopic cerebral angiography is necessary to achieve this aim. The seven patients described developed five types of collateral venous channels: through the basal vein of Rosenthal to the petrosal vein, through the veins on the medial surface of the parietal and occipital lobes to the superior sagittal sinus, through superficial anastomotic veins, through veins of the posterior fossa to the transverse or straight sinus, and through the falcian veins to the superior sagittal sinus. The first three types mainly developed after occlusion of the galenic system. The tumors were removed through the occipital transtentorial approach with a large window at the posterior part of the falx. A favorable prognosis for patients undergoing surgical treatment of falcotentorial junction meningiomas can be expected if detailed neuroimaging studies and microsurgical techniques are used 16).


The tumors were removed subtotally or totally via an occipital interhemispheric transtentorial approach and/or infratentorial supracerebellar approach. The postoperative courses were uneventful, and no neurological deficit was detected postoperatively. Pineal region tumors with a maximum diameter of 5 cm or larger should be operated on via a unilateral or bilateral occipital interhemispheric transtentorial approach, regardless of the angiographic findings, because this permits a wide operative field and can be followed, if necessary, by an infratentorial supracerebellar approach. Selection of the operative approach for a relatively small pineal region tumor should depend on the angiographic findings: downward displacement of the bilateral internal cerebral veins and the great vein of Galen indicates an occipital interhemispheric transtentorial approach, whereas upward displacement indicates an infratentorial supracerebellar approach 17).

Case reports

2017

One representative case of falcotentorial meningioma treated through an anterior interhemispheric transsplenial approach is also described. Among the interhemispheric approaches to the pineal region, the anterior interhemispheric transsplenial approach has several advantages. 1) There are few or no bridging veins at the level of the pericoronal suture. 2) The parietal and occipital lobes are not retracted, which reduces the chances of approach-related morbidity, especially in the dominant hemisphere. 3) The risk of damage to the deep venous structures is low because the tumor surface reached first is relatively vein free. 4) The internal cerebral veins can be manipulated and dissected away laterally through the anterior interhemispheric route but not via the posterior interhemispheric route. 5) Early control of medial posterior choroidal arteries is obtained. The anterior interhemispheric transsplenial approach provides a safe and effective surgical corridor for patients with supratentorial pineal region tumors that 1) extend superiorly, involve the splenium of the corpus callosum, and push the deep venous system in a posterosuperior or an anteroinferior direction; 2) are tentorial and displace the deep venous system inferiorly; or 3) originate from the splenium of the corpus callosum 18).

2006

Kawashima et al. reported, in anatomic studies, a occipital transtentorial approach: the occipital bi-transtentorial/falcine approach, to treat such lesions. Gusmão et al. present a patient with a large falcotentorial meningioma, located bilaterally in the posterior incisural space. The occipital bi-transtentorial/falcine approach allowed an excellent surgical exposure and complete tumor removal with an excellent patient outcome 19).

References

1) , 15)

Okami N, Kawamata T, Hori T, Takakura K. Surgical treatment of falcotentorial meningioma. J Clin Neurosci. 2001 May;8 Suppl 1:15-8. Review. PubMed PMID: 11386819.
2)

Raco A, Agrillo A, Ruggeri A, Gagliardi FM, Cantore G. Surgical options in the management of falcotentorial meningiomas: report of 13 cases. Surg Neurol. 2004 Feb;61(2):157-64; discussion 164. PubMed PMID: 14751629.
3) , 7)

Sekhar LN, Goel A. Combined supratentorial and infratentorial approach to large pineal-region meningioma. Surg Neurol. 1992 Mar;37(3):197-201. PubMed PMID: 1536024.
4) , 6) , 11)

Hong CK, Hong JB, Park H, Moon JH, Chang JH, Lee KS, Park SW. Surgical Treatment for Falcotentorial Meningiomas. Yonsei Med J. 2016 Jul;57(4):1022-8. doi: 10.3349/ymj.2016.57.4.1022. PubMed PMID: 27189300; PubMed Central PMCID: PMC4951445.
5) , 12)

Quiñones-Hinojosa A, Chang EF, Chaichana KL, McDermott MW. Surgical considerations in the management of falcotentorial meningiomas: advantages of the bilateral occipital transtentorial/transfalcine craniotomy for large tumors. Neurosurgery. 2009 May;64(5 Suppl 2):260-8; discussion 268. doi: 10.1227/01.NEU.0000344642.98597.A7. PubMed PMID: 19287325.
8)

Hwang SK, Gwak HS, Paek SH, Kim DG, Jung HW. Guidelines for the ligation of the sigmoid or transverse sinus during large petroclival meningioma surgery. Skull Base. 2004 Feb;14(1):21-8; discussion 29. PubMed PMID: 16145581; PubMed Central PMCID: PMC1151668.
9)

Al-Mefty O, Fox JL, Smith RR. Petrosal approach for petroclival meningiomas. Neurosurgery. 1988 Mar;22(3):510-7. PubMed PMID: 3362317.
10)

Hitselberger WE, House WF. A combined approach to the cerebellopontine angle. A suboccipital-petrosal approach. Arch Otolaryngol. 1966 Sep;84(3):267-85. PubMed PMID: 5296435.
13)

Goto T, Ohata K, Morino M, Takami T, Tsuyuguchi N, Nishio A, Hara M. Falcotentorial meningioma: surgical outcome in 14 patients. J Neurosurg. 2006 Jan;104(1):47-53. PubMed PMID: 16509146.
14)

Quinones-Hinojosa A, Chang EF, McDermott MW. Falcotentorial meningiomas: clinical, neuroimaging, and surgical features in six patients. Neurosurg Focus. 2003 Jun 15;14(6):e11. Review. PubMed PMID: 15669786.
16)

Asari S, Maeshiro T, Tomita S, Kawauchi M, Yabuno N, Kinugasa K, Ohmoto T. Meningiomas arising from the falcotentorial junction. Clinical features, neuroimaging studies, and surgical treatment. J Neurosurg. 1995 May;82(5):726-38. Review. PubMed PMID: 7714596.
17)

Matsuda Y, Inagawa T. Surgical removal of pineal region meningioma–three case reports. Neurol Med Chir (Tokyo). 1995 Aug;35(8):594-7. PubMed PMID: 7566392.
18)

Yağmurlu K, Zaidi HA, Kalani MY, Rhoton AL Jr, Preul MC, Spetzler RF. Anterior interhemispheric transsplenial approach to pineal region tumors: anatomical study and illustrative case. J Neurosurg. 2017 Jan 13:1-11. doi: 10.3171/2016.9.JNS16279. [Epub ahead of print] PubMed PMID: 28084911.
19)

Gusmão S, Oliveira MM, Arantes A, Ulhoa TH, Morato EG. Occipital bi-transtentorial/falcine approach for falcotentorial meningioma: case report. Arq Neuropsiquiatr. 2006 Mar;64(1):136-8. Epub 2006 Apr 5. PubMed PMID: 16622571.

Update: Atypical meningioma

Atypical meningioma (AM)

Atypical (WHO Grade IImeningiomas comprise a heterogeneous group of tumors, with histopathology delineated under the guidance of the WHO and a spectrum of clinical outcomes.
In atypical meningiomas bone involvement and large meningioma peritumoral edema are associated with increased tumor progression.

Classification

Intracranial atypical meningiomas
Spinal atypical meningiomas

Epidemiology

Approximately 15-20% of meningiomas are atypical, meaning that the tumor cells do not appear typical or normal. Atypical meningiomas are neither malignant (cancerous) nor benign, but may become malignant.

Treatment

The treatment of atypical meningioma remains controversial and under-investigated in prospective studies. The roles of surgery, radiation therapy, radiosurgery, and chemotherapy have been incompletely delineated. This has left physicians to decipher how they should treat patients on a case-by-case basis.
In a study, Sun et al. review the English-language literature on the management and clinical outcomes using the WHO 2000/2007 grading criteria. Twenty-two studies for AMs were examined in detail. The authors examined clinical decision points using the literature and concepts from evidence-based medicine. Acknowledging the retrospective nature of the studies, the authors did find evidence for the following clinical strategies:
1) maximal safe resection
2) active surveillance after gross-total resection
3) adjuvant radiation therapy after subtotal resection of AM, especially in the absence of putative radio resistant features 1).

Postoperative radiotherapy

Atypical meningiomas are increasingly irradiated, even after complete or near-complete microsurgical resection despite data that suggests that close observation remains reasonable in the setting of aggressive microsurgical resection.
The efficacies of adjuvant stereotactic radiosurgery (SRS) and external beam radiation therapy (EBRT) for atypical meningiomas (AMs) after subtotal resection (STR) remain unclear.
Conformal, high dose radiotherapy resulted in significant improvement of local control for atypical and malignant meningiomas. Increased local control resulted also in improved rates of survival for patients with malignant meningioma 2).
Role of necrosis
Adjuvant radiation therapy or external beam radiation therapy (EBRT) improved local control after stereotactic radiosurgery STR but only for tumors without spontaneous necrosis. Spontaneous necrosis may aid in decisions to administer adjuvant SRS or EBRT after STR of AMs 3).
Necrosis may be a negative predictor of radiation response regardless of radiation timing or modality 4).

Recurrence

Grade II atypical meningiomas tend to recur and grow faster.
Retrospective series supports the observation that postoperative radiotherapy likely results in lower recurrence rates of gross totally resected atypical meningiomas.
Patients older than 55 years and those with mitoses noted during pathological examination had a significant risk of recurrence after GTR; for these patients, postoperative radiotherapy is recommended 5).
After GTR without postoperative radiation, AMs have a high recurrence rate. Most recurrences occurred within 5 years after resection. Recurrences caused numerous reoperations per patient and shortened survival 6).
A multicenter prospective trial will ultimately be needed to fully define the role of radiotherapy in managing gross totally resected atypical meningiomas 7).
Study limitations, including inadequate statistical power, may underlie the studies’ inability to demonstrate a statistically significant benefit for adjuvant radiotherapy in AM. Because these tumors preferentially recur within 5 years of surgical resection, future studies should define whether early adjuvant therapy should become part of the standard treatment paradigm for completely excised tumors 8).
Brain invasion and high mitotic rates may predict recurrence. After gross total resection (GTR) of AMs, EBRT appears not to affect progression free survival and overall survival, suggesting that observation rather than EBRT may be indicated after GTR 9).

Outcome

The rarity and the inconsistent criteria for defining atypical meningioma prior to the WHO 2007 classification made its management and prognostic factors poorly understood. Only few articles have addressed the survival rates of WHO-classified atypical meningiomas. The small number or the disproportionate representation of irradiated patients was a weakness for these articles.
The most important prognostic factor in determining recurrence was Simpson grading. There was no statistically significant impact of adjuvant radiotherapy on the recurrence of atypical meningiomas. Metaanalysis for the existing literature is needed 10).

Case series

2017

The National Cancer Database was used to identify 2515 patients who were diagnosed with AM between 2009 and 2012 and underwent STR or GTR with or without adjuvant RT. Propensity score matching was first applied to balance covariates including age, year of diagnosis, sex, race, histology, and tumor size in STR or GTR cohorts stratified by adjuvant RT status. Multivariate regression according to the Cox proportional hazards model and Kaplan-Meier survival plots with log-rank test were then used to evaluate OS difference associated with adjuvant RT.
GTR is associated with improved OS compared with STR. In the subgroup analysis, adjuvant RT in patients who underwent STR demonstrated significant association with improved OS compared with no adjuvant RT (adjusted hazard ratio [AHR] 0.590, P = .045); however, adjuvant RT is not associated with improved OS in patients who underwent GTR (AHR 1.093, P = .737).
Despite the lack of consensus on whether adjuvant RT reduces recurrence after surgical resection of AM, our study observed significantly improved OS with adjuvant RT compared with no adjuvant RT after STR 11).

2016

Real-Peña et al published 27 patients with pathological diagnosis of atypical meningioma, and who had a minimum follow-up time of 6 months after diagnosis. Later prognostic factors (age <50years, male gender, bone involvement, peri-lesional swelling, tumour volume, location, Ki67/MIB-1) were evaluated after the stratification of patients undergoing complete resection in recurrencies and non-recurrencies. Univariate analysis was performed using Mann-Whitney test, χ(2) homogeneity test/Fisher exact test. Finally, multivariate analysis was performed using binary logistic regression to obtain the values for R(2) Nagelkerke and the Hosmer-Lemeshow to evaluate the goodness of fit.
The uni- and multivariate analysis showed no statistically significant differences between recurrent and non-recurrent subgroups of patients undergoing complete resection. It is noted in the results that for each year of age above 50 years, the risk of recurrence is decreased by 5.8%.
Although current prognostic factors may show an increased risk of recurrence once patients are stratified by the two most important factors (pathology and extent of resection), those factors are insufficient to predict the ultimate outcome of patients affected by this pathology 12)


Endo et al., reviewed 45 patients with atypical meningioma who underwent surgical intervention between January 2000 and December 2013. The mean age of the patients and mean follow-up period was 58.7 years and 81.0 months, respectively. Analyses included factors such as patient age, gender, location and size of tumor, extent of surgical resection (Simpson Grading System), and MIB-1 index (LI). Univariate analysis was used to detect prognostic factors associated with recurrence and survival.
The 5-year recurrence-free rate for all 45 patients was 58.4 %; 5- and 10-year survival rates were 83.2 % and 79.9 %, respectively. In univariate analyses, age >60 years, and MIB-1 LI correlated with disease recurrence, whereas age >60 years, subtotal surgical resection, MIB-1 LI, and indication for radiotherapy correlated with death. MIB-1 LI levels higher than 12.8 % and 19.7 % predicted recurrence and death, respectively. In our cohort, 26 patients received postoperative radiotherapy including conventional radiation (n = 21) or gamma knife radiosurgery (n = 5). Postoperative radiotherapy did not decrease recurrence rates in our cohort (p = 0.63). Six and two patients who died during the study period underwent conventional radiation and radiosurgery, respectively.
Age, male gender, extent of surgical resection, and higher MIB-1 LI influenced the outcome of atypical meningioma. In our cohort, postoperative radiotherapy failed to provide long-term tumor control. Following incomplete surgical resection of atypical meningioma in elderly patients, adjuvant postoperative radiotherapy may not be an ideal treatment option, particularly when MIB-1 LI is higher than 19.7 % 13).


44 WHO Grade II and 9 WHO Grade III meningiomas treated by CyberKnife for adjuvant or salvage therapy. Patient demographics, treatment parameters, local control, regional control, locoregional control, overall survival, radiation history, and complications were documented.
For WHO Grade II patients, recurrence occurred in 41%, with local, regional, and locoregional failure at 60 months recorded as 49%, 58% and 36%, respectively. For WHO Grade III patients, recurrence occurred in 66%, with local, regional, and locoregional failure at 12 months recorded as 57%, 100%, and 43%. The 60-month locoregional control rates for radiation naïve and experienced patients were 48% and 0% (p = 0.14), respectively. Overall, 7 of 44 Grade II patients and 8 of 9 Grade III patients had died at last follow-up. The 60-month and 12-month overall survival rates for Grade II and III meningioma were 87% and 50%, respectively. Serious complications occurred in 7.5% of patients.
SRS for adjuvant and salvage treatment of WHO Grade II meningioma by a hypofractionated plan is a viable treatment strategy with acceptable long-term tumor control, overall survival, and complication rates. Future work should contribute additional study toward the radiation naïve and the local management of malignant meningioma 14).


A triple center case-note review of adults with newly-diagnosed atypical meningiomas between 2001 and 2010 was performed. Pathology diagnosis was made according to the World Health Organization classification in use at the time of surgery. Patients with multiple meningiomas, neurofibromatosis type 2 and radiation-induced meningiomas were excluded. Extent of resection was defined as gross total resection (GTR; Simpson Grade I-III) or subtotal resection (STR; Simpson Grade IV-V). Survival analysis was performed using the Kaplan-Meier method. One hundred thirty-three patients were identified with a median age of 62years (range 22-86years) and median follow-up of 57.4months (range 0.1-152.2months). Tumors were mostly located in the convexity (50.4%) or falcine/parasagittal regions (27.1%). GTR (achieved in 85%) was associated with longer progression free survival (PFS) (5year PFS 81.2% versus 40.08%, log-rank=11.117, p=0.001) but not overall survival (OS) (5year OS 76.6% versus 39.7%, log-rank=3.652, p=0.056). Following GTR, early adjuvant radiotherapy was administered to 28.3% of patients and did not influence OS (5year OS 77.0% versus 75.7%, log-rank=0.075, p=0.784) or PFS (5year PFS 82.0% versus 79.3%, log-rank=0.059, p=0.808). Although extent of resection emerged as an important prognostic variable, early adjuvant radiotherapy did not influence outcome following GTR of atypical meningiomas. Prospective randomized controlled trials are planned 15).

2015

Twenty-eight patients with skull base atypical meningiomas underwent microsurgical resection between June 2001 and November 2009. The clinical characteristics of the patients and meningiomas, the extent of surgical resection, and complications after treatment were retrospectively analyzed.
Thirteen patients (46.4%) had disease recurrence or progression during follow up time. The median time to disease progression was 64 months. The extent of the surgical resection significantly impacted prognosis. Gross total resection (GTR) of the tumor improved progression free survival (PFS) compared to subtotal resection (STR, p = 0.011). An older patient age at diagnosis also resulted in a worse outcome (p = 0.024). An MIB-1 index <8% also contributed to improved PFS (p = 0.031). None of the patients that underwent GTR and received adjuvant radiotherapy had tumors recur during follow up. STR with adjuvant radiotherapy tended to result in better local tumor control than STR alone (p = 0.074). Three of 28 patients (10.7%) developed complications after microsurgery. The GTR group had a higher rate of complications than those with STR. There were no late adverse effects after adjuvant radiotherapy during follow up.
For patients with skull base atypical meningiomas, GTR is desirable for longer PFS, unless radical excision is expected to lead to severe complications. Adjuvant radiation therapy is advisable to reduce tumor recurrence regardless of the extent of surgical resection. Age of disease onset and the MIB-1 index of the tumor were both independent prognostic factors of clinical outcome 16).


A retrospective analysis of the patients operated at the Clinic of Neurosurgery, Clinical Center of Serbia, Belgrade, between January 1st 1995 and December 31th 2006 was performed. In that period 88 lesions met the histological criteria for atypical (75) and anaplastic (13) meningioma. Postoperative radiotherapy was conducted in 63.6% of patients.
At a median follow-up of 67.4 months in all patients the overall survival was 68 months and five-year survival was about 54.5%. The median survival was 76 months with surgery and adjuvant radiotherapy and 40 months with surgery alone (Log rank=7.4; p=0.006). Recurrent disease occurred in 58 patients (65.9%). Median time between first surgery and tumor recurrence in patients undergoing radiotherapy was 51 months, while in non-irradiated group 24 months (Log rank=17.7; p˂0.001). Multivariate analysis identified as recurrence-predicting factors anaplastic histotype (hazard ratio=2,9; p=0,003) and postoperative radiotherapy (hazard ratio=4,5; p<0,001).
The addition of adjuvant radiotherapy to surgery for atypical and anaplastic meningiomas resulted in a clinically meaningful and statistically significant survival benefit 17).

Case reports

Only two prior cases of benign dendritic melanocytes colonizing a meningioma have been reported.
Dehghan Harati et al. add a third case, describe clinicopathologic features shared by the three, and elucidate the risk factors for this very rare phenomenon. A 29 year-old Hispanic woman presented with headache and hydrocephalus. MRI showed a lobulated enhancing pineal region mass measuring 41 mm in greatest dimension. Subtotal resection of the mass demonstrated an atypical meningioma, WHO grade II, and the patient subsequently underwent radiotherapy. She presented 4 years later with diplopia, and MRI showed an enhancing extra-axial mass measuring 47 mm in greatest dimension and centered on the tentorial incisura. Subtotal resection showed a brain-invasive atypical meningioma with melanocytic colonization. The previous two cases in the literature were atypical meningiomas, one of which was also brain invasive. Atypical meningiomas may be at particular risk for melanocytic colonization as they upregulate molecules known to be chemoattractants for melanocytes. We detected c-Kit expression in a minority of the melanocytes as well as stem cell factor and basic fibroblast growth factor in the meningioma cells, suggesting that mechanisms implicated in normal melanocyte migration may be involved. In some cases, brain invasion with disruption of the leptomeningeal barrier may also facilitate migration from the subarachnoid space into the tumor. Whether there is low-level proliferation of the dendritic melanocytes is unclear. Given that all three patients were non-Caucasian, meningiomas in persons and/or brain regions with increased dendritic melanocytes may predispose to colonization. The age range spanned from 6 years old to 70 years old. All three patients were female. The role of gender and estrogen in the pathogenesis of this entity remains to be clarified. Whether melanocytic colonization may also occur in the more common Grade I meningiomas awaits identification of additional cases 18).

References

1)

Sun SQ, Hawasli AH, Huang J, Chicoine MR, Kim AH. An evidence-based treatment algorithm for the management of WHO Grade II and III meningiomas. Neurosurg Focus. 2015 Mar;38(3):E3. doi: 10.3171/2015.1.FOCUS14757. PubMed PMID: 25727225.
2)

Hug EB, Devries A, Thornton AF, Munzenride JE, Pardo FS, Hedley-Whyte ET, Bussiere MR, Ojemann R. Management of atypical and malignant meningiomas: role of high-dose, 3D-conformal radiation therapy. J Neurooncol. 2000 Jun;48(2):151-60. PubMed PMID: 11083080.
3)

Sun SQ, Cai C, Murphy RK, DeWees T, Dacey RG, Grubb RL, Rich KM, Zipfel GJ, Dowling JL, Leuthardt EC, Leonard JR, Evans J, Simpson JR, Robinson CG, Perrin RJ, Huang J, Chicoine MR, Kim AH. Management of atypical cranial meningiomas, part 2: predictors of progression and the role of adjuvant radiation after subtotal resection. Neurosurgery. 2014 Oct;75(4):356-63. doi: 10.1227/NEU.0000000000000462. PubMed PMID: 24932708.
4)

Sun SQ, Cai C, Murphy RK, DeWees T, Dacey RG, Grubb RL, Rich KM, Zipfel GJ, Dowling JL, Leuthardt EC, Simpson JR, Robinson CG, Chicoine MR, Perrin RJ, Huang J, Kim AH. Radiation Therapy for Residual or Recurrent Atypical Meningioma: The Effects of Modality, Timing, and Tumor Pathology on Long-Term Outcomes. Neurosurgery. 2016 Jul;79(1):23-32. doi: 10.1227/NEU.0000000000001160. PubMed PMID: 26645969.
5)

Lee KD, DePowell JJ, Air EL, Dwivedi AK, Kendler A, McPherson CM. Atypical meningiomas: is postoperative radiotherapy indicated? Neurosurg Focus. 2013 Dec;35(6):E15. doi: 10.3171/2013.9.FOCUS13325. PubMed PMID: 24289123.
6)

Aghi MK, Carter BS, Cosgrove GR, Ojemann RG, Amin-Hanjani S, Martuza RL, Curry WT Jr, Barker FG 2nd. Long-term recurrence rates of atypical meningiomas after gross total resection with or without postoperative adjuvant radiation. Neurosurgery. 2009 Jan;64(1):56-60; discussion 60. doi: 10.1227/01.NEU.0000330399.55586.63. PubMed PMID: 19145156.
7)

Komotar RJ, Iorgulescu JB, Raper DM, Holland EC, Beal K, Bilsky MH, Brennan CW, Tabar V, Sherman JH, Yamada Y, Gutin PH. The role of radiotherapy following gross-total resection of atypical meningiomas. J Neurosurg. 2012 Oct;117(4):679-86. doi: 10.3171/2012.7.JNS112113. Epub 2012 Aug 24. PubMed PMID: 22920955.
8)

Kaur G, Sayegh ET, Larson A, Bloch O, Madden M, Sun MZ, Barani IJ, James CD, Parsa AT. Adjuvant radiotherapy for atypical and malignant meningiomas: a systematic review. Neuro Oncol. 2014 May;16(5):628-36. doi: 10.1093/neuonc/nou025. Epub 2014 Apr 2. PubMed PMID: 24696499; PubMed Central PMCID: PMC3984561.
9)

Sun SQ, Kim AH, Cai C, Murphy RK, DeWees T, Sylvester P, Dacey RG, Grubb RL, Rich KM, Zipfel GJ, Dowling JL, Leuthardt EC, Leonard JR, Evans J, Simpson JR, Robinson CG, Perrin RJ, Huang J, Chicoine MR. Management of atypical cranial meningiomas, part 1: predictors of recurrence and the role of adjuvant radiation after gross total resection. Neurosurgery. 2014 Oct;75(4):347-55. doi: 10.1227/NEU.0000000000000461. PubMed PMID: 24932707.
10)

Hammouche S, Clark S, Wong AH, Eldridge P, Farah JO. Long-term survival analysis of atypical meningiomas: survival rates, prognostic factors, operative and radiotherapy treatment. Acta Neurochir (Wien). 2014 Aug;156(8):1475-81. doi: 10.1007/s00701-014-2156-z. Epub 2014 Jun 26. PubMed PMID: 24965072.
11)

Wang C, Kaprealian TB, Suh JH, Kubicky CD, Ciporen JN, Chen Y, Jaboin JJ. Overall survival benefit associated with adjuvant radiotherapy in WHO grade II meningioma. Neuro Oncol. 2017 Mar 24. doi: 10.1093/neuonc/nox007. [Epub ahead of print] PubMed PMID: 28371851.
12)

Real-Peña L, Talamantes Escribá F, Quilis-Quesada V, González-Darder JM. [Prognostic variability in atypical meningioma with complete resection. Proposed treatment algorithm]. Neurocirugia (Astur). 2016 Jan-Feb;27(1):15-23. doi: 10.1016/j.neucir.2015.08.003. Spanish. PubMed PMID: 26687847.
13)

Endo T, Narisawa A, Ali HS, Murakami K, Watanabe T, Watanabe M, Jokura H, Endo H, Fujimura M, Sonoda Y, Tominaga T. A study of prognostic factors in 45 cases of atypical meningioma. Acta Neurochir (Wien). 2016 Sep;158(9):1661-7. doi: 10.1007/s00701-016-2900-7. Epub 2016 Jul 28. PubMed PMID: 27468919.
14)

Zhang M, Ho AL, D’Astous M, Pendharkar AV, Choi CY, Thompson PA, Tayag AT, Soltys SG, Gibbs IC, Chang SD. CyberKnife Stereotactic Radiosurgery for Atypical and Malignant Meningiomas. World Neurosurg. 2016 Apr 20. pii: S1878-8750(16)30092-4. doi: 10.1016/j.wneu.2016.04.019. [Epub ahead of print] PubMed PMID: 27108030.
15)

Jenkinson MD, Waqar M, Farah JO, Farrell M, Barbagallo GM, McManus R, Looby S, Hussey D, Fitzpatrick D, Certo F, Javadpour M. Early adjuvant radiotherapy in the treatment of atypical meningioma. J Clin Neurosci. 2016 Jan 8. pii: S0967-5868(15)00663-3. doi: 10.1016/j.jocn.2015.09.021. [Epub ahead of print] PubMed PMID: 26775147.
16)

Wang YC, Chuang CC, Wei KC, Hsu YH, Hsu PW, Lee ST, Wu CT, Tseng CK, Wang CC, Chen YL, Jung SM, Chen PY. Skull base atypical meningioma: long term surgical outcome and prognostic factors. Clin Neurol Neurosurg. 2015 Jan;128:112-6. doi: 10.1016/j.clineuro.2014.11.009. Epub 2014 Nov 24. PubMed PMID: 25486076.
17)

Pisćević I, Villa A, Milićević M, Ilić R, Nikitović M, Cavallo LM, Grujičić D. The influence of adjuvant radiotherapy in atypical and anaplastic meningiomas: a series of 88 patients in a single institution. World Neurosurg. 2015 Mar 10. pii: S1878-8750(15)00128-X. doi: 10.1016/j.wneu.2015.02.021. [Epub ahead of print] PubMed PMID: 25769488.
18)

Dehghan Harati M, Yu A, Magaki SD, Perez-Rosendahl M, Im K, Park YK, Bergsneider M, Yong WH. Clinicopathologic features and pathogenesis of melanocytic colonization in atypical meningioma. Neuropathology. 2017 Aug 18. doi: 10.1111/neup.12409. [Epub ahead of print] PubMed PMID: 28833600.

Update: Falx Meningioma

Falx or falcine meningioma, as defined by Harvey Williams Cushing, is a meningioma arising from the falx cerebri and completely concealed by the overlying cortex 1).
Not involving the superior sagittal sinus.

Epidemiology

Falcine meningiomas account for 9% of all intracranial meningiomas.
Falcine meningioma tends to grow predominately into one cerebral hemisphere but is often bilateral, and in some patients the tumor grows into the inferior edge of the sagittal sinus.
The patients with falcine meningiomas with reference to gender had the following ratio of male:female of 1:2.1 and an average age of 55 years.
In the series of Pires de Aguiar et al 1:6 (men:women) relationship, and the mean age was 55.4 years old 2).

Classification

They can be divided into anterior, middle, and posterior types, depending on their origin in the falx 3).
The anterior type extends from the floor of the anterior cranial fossa to the coronal suture, the middle type from the coronal suture to the lambdoid suture, and the posterior type extends from the lambdoid suture to the torcular Herophili.
Falcine meningioma of the anterior third
Falcine meningioma of the middle third
Falcine meningioma of the posterior third.
Yasargil classified falcine meningiomas into outer and inner types. The former arise from the main body of the falx in the frontal (anterior or posterior), central parietal, or occipital regions, whereas inner falcine meningiomas arise in conjunction with the inferior sagittal sinus4).
Zuo et al classified FM into four types, according to tumour growth patterns on coronal MRI: Type I, hemispheroid-shaped tumours invaginating deeply into one hemisphere without shifting the falx (10 patients); Type II, olive-shaped tumours shifting the falx substantially to the contralateral side (six patients); Type IIIA, globular- or dumbbell-shaped tumours extending into both hemispheres, but to different extents (one patient); and Type IIIB, globular- or dumbbell-shaped tumours extending into both hemispheres to approximately equal extent (three patients). An ipsilateral interhemispheric approach was performed for Type I tumours, and a contralateral transfalcine approach for Type II. Type IIIA tumour was approached from the side where the smaller tumour was located. Type IIIB tumours were approached from the non-dominant hemisphere 5).


see also cystic falx meningioma.

Clinical features

Symptoms can vary depending upon the location of these tumors along the falx.
Those located in the frontal section may impair higher levels of brain functioning such as reasoning and memory, while those located in the middle section would be more likely to cause leg weakness.

Diagnosis

MRI with and without gadolinium helps better to delineate the tumor in relation to the dural sinus, the tumor interface with the cerebral cortex, presence of significant blood supply, and presence of cysts or other intra-tumoral structures that will add to the complexity and malignant potential of the tumor. Good pre-operative evaluation of falcine meningiomas is also important when integrated with neuronavigation protocols to be utilized in the operating room. Furthermore, the junction between tumor and adjacent brain suggests the presence or absence of an accessible arachnoid plane and enables the surgeon to predict the potential degree of neurologic deficit that may follow surgical removal. Gadolinium-enhanced MRI allows demonstration of tumoral or adjancent dural enhancement. The radiological appearance affords a valid predictor of the degree of dural involvement in the region of the sinus and adjacent falx. This may suggest the presence of syncytium of meningeal cells spreading along the falx from the site of major dural attachment.
Multiplanar MRI is the current standard study for the preoperative evaluation of patients with falcine meningiomas. Coronal, sagittal, and axial T1-weighted gadolinium-enhanced sequences help define the anatomical locations, sizes, and medial hemisphere involvements of these tumors.
MR venography in vertex view can be useful for demonstrating nearby parasagittal draining veins, which must be protected 6) , but MRA alone seems to be inadequate in the lack of venous phase of cerebral vasculature around tumors.

Cerebral angiography

Cerebral angiography is necessary in patients with these meningiomas, and the pericallosal artery is often displaced and may actually be engulfed by the tumor. Arterial phase cerebral or MR angiograms should be studied to determine the relationship between tumor and ACA. Anterior falcine meningiomas are usually supplied by the ACA or by a tentorial branch of the ophthalmic artery. Venous phase cerebral angiography is important because it provides significant information about whether a tumor mass has invaded the sagittal sinus. Moreover, it provides information about the courses of many large drainers around a mass, which must be determined to identify trajectory to a falcine mass and to prevent postoperative venous infarction. It is also useful for determining sinus patency and for delineating the anatomical location of the major cortical draining vein. Signs of venous occlusion include the disappearance of a segment of the superior sagittal sinus (SSS), a delay in venous drainage in the area of obstruction, and failure of the cortical vein to reach the sinus.

Differential diagnosis

There are several tumors that grow near the falx and may mimic the falcine meningiomas. Osteochondromas, chondrosarcomas, solitary fibrous tumor of the meninges, epidermoid tumors and metastasis are the most frequent.
Although rare, marginal zone B-cell lymphoma must be considered in the differential diagnosis of an extra-axial enhancing mass 7).


A 43-year-old man arrived at the emergency department following a syncopal episode. Computed tomography and magnetic resonance images demonstrated a small interhemispheric, anterior parafalcine mass that mimicked a meningioma. Surgical excision and subsequent pathologic evaluation revealed an angioleiomyoma and the patient recovered without incident 8).


see Granulocytic sarcoma

Treatment

The pure falcine meningiomas (without relation with cortical surface and superior sagittal sinus) and parasagittal falcine meningiomas may arise at any point along the midline, anterior to posterior, and present different technical problems depending on their location and depth.
Cushing and Eisenhardt used a transcortical incision to expose most falcine meningiomas. However, current microsurgical techniques and methods have improved intracranial compliance, including cerebrospinal fluid drainage, mannitolization, and hyperventilation, and a transcortical approach is rarely required 9).
The dura is opened to I to 2 cm from the midline, with the expo­sure planned in relation to the cortical veins draining to the sagittal sinus. Arachnoid and pacchionian granulation attachments are divided. It is only necessary to retract the medial cerebral cortex I to 2 cm from the falx to expose the tumor. In some cases a bridging vein can be freed from the cortex for a few millimeters to give the required exposure without sacrificing the vein. A self­retaining retractor is placed. In the anterior third it is usually possible to take the draining veins and the sagittal sinus if necessary to complete the resection.
The key to the operation is to carry out an extensive internal decompression of the tumor with the ultrasonic aspirator and grad­ually draw the capsule into the area of decompression. Sometimes the tumor is transected parallel to the falx so the capsule can be more easily mobilized. In some patients a bilateral exposure is required. At some point in the operation, depending on the size and configuration of the tumor, the falx is divided well away from the tumor attachment. The inferior sagittal sinus can be occluded. Great care must be taken not to injure the pericallosal and calloso­marginal arteries.


Spektor et al described a purely endoscopic removal of an atypical parasagittal meningioma in a patient who could not undergo standard craniotomy due to severe scalp atrophy following childhood irradiation for tinea capitis 10).
For treating a patient with multiple falcine and parasagittal lesions, Yamaguchi et al. believe that it is beneficial to resect the maximum possible number of lesions during one operation, even if some lesions are asymptomatic. This practice can potentially reduce the total number of operations during a patient’s lifetime 11).

Complications

The falcine meningiomas may be present with bleeding as intraparenchymal hematomas, subdural hematomas and subarachnoid hemorrhage, causing a clinical finding of apoplexy in the patients.
Hemorrhages occurring in asymptomatic falcine meningiomas are known beforehand to have been described after the internal use of low-dose aspirin for prolonged period.
During falcine meningioma surgery, we must pay attention to cardiac monitoring due to the risk that the handling of falx and tentorium could provoke cardiac asystole. The mechanical stimulation of the falcine area may result in the hyperactivity of the trigeminal ganglion, thereby triggering TCR.
The dorsal region of the spinal trigeminal tract includes neurons from hypoglossal and vagus nerves, and projections have been seen between the vagus and trigeminal nuclei.

Recurrence

It has been reported that parasagittal meningioma and falx meningiomas recur more frequently than other intracranial meningiomas12).
The rate of recurrence of falx meningiomas significantly increases in cases of non-radical resection of tumor. Aggressive surgical treatment obviously may present several hazards and may carry an increased risk of unsatisfactory outcome; however, the risk of recurrence is significantly decreased 13).
Abou Al-Shaar et al. have utilized brachytherapy as a salvage treatment in two patients with a unique implantation technique. Both patients had recurrence of WHO Grade II falcine meningiomas despite multiple prior surgical and RT treatments. Radioactive I-125 seeds were made into strands and sutured into a mesh implant, with 1 cm spacing, in a size appropriate to cover the cavity and region of susceptible falcine dura. Following resection the vicryl mesh was implanted and fixed to the margins of the falx. Implantation in this interhemispheric space provides good dose conformality with targeting of at-risk tissue and minimal radiation exposure to normal neural tissues. The patients are recurrence free 31 and 10 months after brachytherapy treatment. Brachytherapy was an effective salvage treatment for the recurrent aggressive falcine meningiomas in two patients 14).

Videos

Books

Parasagittal and falx meningiomas 1970 by P. C Gautier-Smith (Author)
Publisher: Appleton-Century-Crofts (1970) Language: English ISBN-10: 0407352406 ISBN-13: 978-0407352407.

Case series

2017

Murrone et al. analyzed 95 patients with falcine meningiomas who underwent surgical removal of their lesion at our institution between 2001 and 2014. Surgical management of these patients, focusing on anatomical and clinical features is described. Thus, based on our series, a surgical algorithm, classifying the falcine meningioma into four types, according to location at the falx, and using an ipsilateral interhemispheric approach in supine or prone position, is described. The median length of follow-up was 7.1years (range 1.6-12.3years). Approximately one-third of all patients was asymptomatic, headaches occurred in 27 patients, seizures in 14 cases, and lower-extremity weakness in 9 cases. In this series, the middle third of the falx was the most frequently involved site (55,78%), while the anterior third (26,31%) and the posterior type (17,89%) were less common. The transitional and meningothelial types occurred in 69 of patients and a high grade in only two patients. Compared with previous series in literature, there was no mortality and Gross Total Resection was obtained in 83 (87,5%) cases. Three of 95 patients experienced new or worsened neurological deficits after surgery while other complications were relatively in only 6 cases. This study presents our good results about removal of the tumor while preserving major cortical veins and the sinus using advanced microsurgical tools 15).

2007

68 patients with meningiomas arising from the falx underwent craniotomies. There were 22 male and 46 female patients (1 : 2.1). Mean age was 55 years and ranged from 14 to 77 years. Locations of falcine meningioma were; the anterior third in 33 cases, middle in 20, and falcine meningioma of the posterior third in 15.
Mean tumor volume was 42 cc and ranged from 4 to 140 cc. In 58 of the 68 patients tumors were totally removed. Additional surgery for recurrence was performed in 6 patients over 15 years. Of these 6 patients, only two patients underwent gross total tumor resection at first operation; the other four underwent subtotal tumor resection. Based on pathologic reports, the largest tumor subtype was transitional. There were four patients with a high grade tumor-three atypical and one anaplastic meningioma. Of the 68 patients, 59 achieved a good outcome (no neurological deficit or recurrence), six had temporary complications, two suffered new permanent postoperative deficits, and the remaining one died due to severe brain swelling despite postoperative intensive care. Extent of surgical resection was found to be significantly related to tumor recurrence.
Falcine meningioma accounted for 8.5% of intracranial meningiomas and the transitional meningioma was the most common subtype of falcine meningioma. Gross total resection of tumor was the single most important predictor of an improved surgical outcome 16).
1)

Cushing H, Eisenhardt L. Their Classification, Regional Behavior, Life History, and Surgical End Results: The chiasmal syndrome, in Meningiomas. Suprasellar Meningiomas. 1938:224–49.
2) , 13)

Pires de Aguiar PH, Aires R, Maldaun MV, Tahara A, de Souza Filho AM, Zicarelli CA, Ramina R. Is sagittal sinus resection in falcine meningiomas a factor of bad surgical outcome? Surg Neurol Int. 2010 Oct 25;1:64. doi: 10.4103/2152-7806.71983. PubMed PMID: 21125007; PubMed Central PMCID: PMC2980903.
3)

Al-Mefty O, Becker DP, Lanman TH. Meningiomas. 1991. pp. 345–356.
4)

Yasargil MG. Microneurosurgery. Vol 4. 1996. Meningioma; pp. 134–165.
5)

Zuo FX, Wan JH, Li XJ, Qian HP, Meng XL. A proposed scheme for the classification and surgical planning of falcine meningioma treatment. J Clin Neurosci. 2012 Dec;19(12):1679-83. doi: 10.1016/j.jocn.2012.01.034. Epub 2012 Oct 6. PubMed PMID: 23047062.
6)

Alvernia J, Sindou M. Preoperative neuroimaging findings as a predictor of surgical plane of cleavage : Prospective study of 100 consecutive cases of intracranial meningioma. J Neurosurg. 2004;100:422–430.
7)

Douleh DG, Morone PJ, Forbes JA, Thompson RC. Intracranial Marginal Zone B-Cell Lymphoma Mimicking Meningioma. World Neurosurg. 2016 May 4. pii: S1878-8750(16)30235-2. doi: 10.1016/j.wneu.2016.04.106. [Epub ahead of print] PubMed PMID: 27155383.
8)

Calle S, Louis D, Westmark R, Westmark K. Angioleiomyoma of the falx. J Radiol Case Rep. 2016 Apr 30;10(4):8-15. doi: 10.3941/jrcr.v10i4.2713. eCollection 2016 Apr. PubMed PMID: 27200167; PubMed Central PMCID: PMC4861627.
9)

Chung SB, Kim CY, Park CK, Kim DG, Jung HW. Falx meningiomas: surgical results and lessons learned from 68 cases. J Korean Neurosurg Soc. 2007 Oct;42(4):276-80. doi: 10.3340/jkns.2007.42.4.276. Epub 2007 Oct 20. PubMed PMID: 19096556; PubMed Central PMCID: PMC2588203.
10)

Spektor S, Margolin E, Eliashar R, Moscovici S. Purely endoscopic removal of a parasagittal/falx meningioma. Acta Neurochir (Wien). 2016 Mar;158(3):451-6. doi: 10.1007/s00701-015-2689-9. Epub 2016 Jan 8. PubMed PMID: 26746827.
11)

Yamaguchi J, Watanabe T, Nagatani T. Endoscopic approach via the interhemispheric fissure: the role of an endoscope in a surgical case of multiple falcine lesions. Acta Neurochir (Wien). 2017 Jul;159(7):1243-1246. doi: 10.1007/s00701-017-3129-9. Epub 2017 Mar 11. PubMed PMID: 28283869.
12)

Melamed S, Sahar A, Bellar AJ. The recurrence of intracranial meningiomas. Neurochirurgia. 1979;22:47–51.
14)

Abou Al-Shaar H, Almefty KK, Abolfotoh M, Arvold ND, Devlin PM, Reardon DA, Loeffler JS, Al-Mefty O. Brachytherapy in the treatment of recurrent aggressive falcine meningiomas. J Neurooncol. 2015 Aug 8. [Epub ahead of print] PubMed PMID: 26253325.
15)

Murrone D, De Paulis D, di Norcia V, Di Vitantonio H, Galzio RJ. Surgical management of falcine meningiomas: Experience of 95 patients. J Clin Neurosci. 2017 Mar;37:25-30. doi: 10.1016/j.jocn.2016.11.002. Epub 2016 Nov 22. Review. PubMed PMID: 27884604.
16)

Chung SB, Kim CY, Park CK, Kim DG, Jung HW. Falx meningiomas: surgical results and lessons learned from 68 cases. J Korean Neurosurg Soc. 2007 Oct;42(4):276-80. doi: 10.3340/jkns.2007.42.4.276. Epub 2007 Oct 20. PubMed PMID: 19096556; PubMed Central PMCID: PMC2588203.

Sphenoid wing meningioma

It is a type of anterior skull base meningioma.

These intracranial meningiomas may be associated with hyperostosis of the sphenoid ridge and may be very invasive, spreading to the dura of the frontal, temporal, orbital, and sphenoidal regions. Medially, this tumor may expand into the wall of the cavernous sinus, anteriorly into the orbit, and laterally into the temporal bone.

Epidemiology

The relative incidence of meningiomas of the sphenoid ridge is 17%. This tumor usually arises from the lesser wing of the sphenoid bone. Sphenoid wing meningiomas, or ridge meningiomas, are the most common of the basal meningiomas.

Types

Tumors found in the external third of the sphenoid are of two types: en-plaque and globoid meningiomas.
En plaque meningiomas characteristically lead to slowly increasing proptosis with the eye angled downward. Much of this is due to reactive orbital hyperostosis. With invasion of the tumor into the orbit, diplopia is common.
Patients with globoid meningiomas often present only with signs of increased intracranial pressure. This leads to various other symptoms including headache and a swollen optic disc.
see Medial sphenoid wing meningioma or clinoidal meningioma.
see Meningioma en plaque of the sphenoid ridge.
see Sphenoorbital meningioma

Clinical Features

Tumors growing in the inner wing (clinoidal) most often cause direct damage to the optic nerve leading especially to a decrease in visual acuity, progressive loss of color vision, defects in the field of vision (especially cecocentral), and an afferent pupillary defect.
If the tumor continues to grow and push on the optic nerve, all vision will be lost in that eye as the nerve atrophies.
Proptosis, or anterior displacement of the eye, and palpebral swelling may also occur when the tumor impinges on the cavernous sinus by blocking venous return and leading to congestion. Damage to cranial nerves in the cavernous sinus leads to diplopia.
The Ophthalmic nerve (is often the first affected, leading to diplopia with lateral gaze. The patient will have pain and altered sensation over the front and top of the head.
Horner syndrome may occur if nearby sympathetic fibers are involved.
Endocrine testing is important because pituitary insufficiency has been reported to occur in 22% of patients with anterior skull base meningiomas, including thyroid stimulating hormone (TSH), follicle stimulating hormone (FSH), and luteinizing hormone (LH).

Diagnosis

Following the physical exam, the diagnosis is confirmed with neuro-imaging. Either a head CT or MRI with contrast such as gadolinium is useful, as meningiomas often show homogenous enhancement. Angiography looking for signs like stretched arteries may be used to supplement evaluation of vascular involvement and to determine whether embolization would be helpful if surgery is being considered.
On MRI imaging, T1- and T2-weighted sequences have variable signal intensity, but they enhance intensely and homogeneously after injection of gadolinium. They also tend to exhibit hyperostosis and calcifications which can be seen on either CT or MRI imaging. Additionally, the presence of a dural extension (also known as a dural tail) is helpful in distinguishing a meningioma from fibrous dysplasia.

Differential diagnosis

The differential diagnosis for sphenoid wing meningioma includes other types of tumors such as optic nerve sheath meningioma, cranial osteosarcoma, metastases, and also sarcoidosis.

Treatment

Microsurgery may be the most effective method for the large and giant medial sphenoid wing meningiomas 1).
With the improved requirement of postoperative quality of life in patients, intentional incomplete resection should be considered as an acceptable treatment option. Multivariate analysis confirmed that incomplete resection, poor blood supply, lack of adhesion or encasement of adjacent structure were independent predictive factors for favorable postoperative quality of life. An individual treatment strategy could help improved quality of life 2).

Outcome

Large and giant medial sphenoid wing meningiomas that are located deeply in the skull base where they are closely bounded by cavernous sinus, optic nerve, and internal carotid artery make the gross resection hard to achieve. Also, this kind of meningiomas is often accompanied by a series of severe complications.
For medial sphenoid wing meningiomas, visual loss and abnormalities of cranial nerves III, IV, VI, V1, and V2 may occur because the meningioma may have some degree of encasement of these structures as they ride through the cavernous sinus.
Seizures, paresis, and sensory loss may result depending on potential damage to adjacent brain parenchyma for patients with lateral sphenoid wing meningiomas.
Sphenoid wing meningiomas (SWMs) can encase arteries of the circle of Willis, increasing their susceptibility to intraoperative vascular injury and severe ischemic complications.

Case series

2017

A retrospective review of 75 patients surgically treated for SWM from 2009 to 2015 was undertaken to determine the degree of circumferential vascular encasement (0°-360°) as assessed by preoperative magnetic resonance imaging (MRI). A novel grading system describing “maximum” and “total” arterial encasement scores was created. Postoperative MRIs were reviewed for total ischemia volume measured on sequential diffusion-weighted images.
Of the 75 patients, 89.3% had some degree of vascular involvement with a median maximum encasement score of 3.0 (2.0-3.0) in the internal carotid artery (ICA), M1, M2, and A1 segments; 76% of patients had some degree of ischemia with median infarct volume of 3.75 cm 3 (0.81-9.3 cm 3 ). Univariate analysis determined risk factors associated with larger infarction volume, which were encasement of the supraclinoid ICA ( P < .001), M1 segment ( P < .001), A1 segment ( P = .015), and diabetes ( P = .019). As the maximum encasement score increased from 1 to 5 in each of the significant arterial segments, so did mean and median infarction volume ( P < .001). Risk for devastating ischemic injury >62 cm 3 was found when the ICA, M1, and A1 vessels all had ≥360° involvement ( P = .001). Residual tumor was associated with smaller infarct volumes ( P = .022). As infarction volume increased, so did modified Rankin Score at discharge ( P = .025).
Subtotal resection should be considered in SWM with significant vascular encasement of proximal arteries to limit postoperative ischemic complications 3).

2015

The clinical materials of 53 patients with sphenoid wing meningiomas treated microsurgically between January 2008 and January 2012 were analyzed retrospectively. Follow-up period ranged from 6 to 62 months (median, 34 months). Clinical outcomes including postoperative quality of life and recurrence rate were evaluated. Univariate and multivariate statistical analysis were performed among factors that might influence postoperative quality of life.
The mean age of patients was 49 years. Mean tumor size was 3.9cm. Total tumor resection was achieved in 38 cases (71.7%), subtotal in 10 cases (18.9%) and partial resection in 5 cases (9.4%). Within the follow-up period, ten patients (18.9%) had recurrence and three patients (5.7%) died. In univariate analysis, we found the postoperative Karnofshky Performance Score (KPS) improvement was determined by various factors, including extent of tumor resection, peritumoral edema, tumor blood supply, size, adhesion, encasement and preoperative KPS. However, multivariate analysis showed that complete resection, rich blood supply, adhesion to adjacent structure, encasement of neurovascular were independent predictive factors for worse postoperative KPS.
With the improved requirement of postoperative quality of life in patients, intentional incomplete resection should be considered as an acceptable treatment option. Multivariate analysis confirmed that incomplete resection, poor blood supply, lack of adhesion or encasement of adjacent structure were independent predictive factors for favorable postoperative quality of life. An individual treatment strategy could help improved quality of life 4).

Case reports

2014

Endo et al. report the utility of a pulsed water jet device in meningioma surgery. The presented case is that of a 61-year-old woman with left visual disturbance. MRI demonstrated heterogeneously enhanced mass with intratumoral hemorrhage, indicating sphenoid ridge meningioma on her left side. The tumor invaded the cavernous sinus and left optic canal, engulfing the internal carotid artery in the carotid cistern and encased middle cerebral arteries. During the operation, the pulsed water jet device was useful for dissecting the tumor away from the arteries since it was safe in light of preserving parent arteries. The jet did not cause any vascular injury and did not induce vasospasm as shown by postoperative symptomatology and MRIs. With the aid of pulsed water jet, we could achieve total resection of the tumor except for the piece within the cavernous sinus. The patient had no new neurological deficits after the operation 5).
1)

Yang J, Ma SC, Liu YH, Wei L, Zhang CY, Qi JF, Yu CJ. Large and giant medial sphenoid wing meningiomas involving vascular structures: clinical features and management experience in 53 patients. Chin Med J (Engl). 2013 Dec;126(23):4470-6. PubMed PMID: 24286409.
2) , 4)

Ouyang T, Zhang N, Wang L, Li Z, Chen J. Sphenoid wing meningiomas: Surgical strategies and evaluation of prognostic factors influencing clinical outcomes. Clin Neurol Neurosurg. 2015 May 4;134:85-90. doi: 10.1016/j.clineuro.2015.04.016. [Epub ahead of print] PubMed PMID: 25974397.
3)

McCracken DJ, Higginbotham RA, Boulter JH, Liu Y, Wells JA, Halani SH, Saindane AM, Oyesiku NM, Barrow DL, Olson JJ. Degree of Vascular Encasement in Sphenoid Wing Meningiomas Predicts Postoperative Ischemic Complications. Neurosurgery. 2017 Jun 1;80(6):957-966. doi: 10.1093/neuros/nyw134. PubMed PMID: 28327941.
5)

Endo T, Nakagawa A, Fujimura M, Sonoda Y, Shimizu H, Tominaga T. [Usefulness of pulsed water jet in dissecting sphenoid ridge meningioma while preserving arteries]. No Shinkei Geka. 2014 Nov;42(11):1019-25. doi: 10.11477/mf.1436200025. Japanese. PubMed PMID: 25351797.
WhatsApp WhatsApp us
%d bloggers like this: