Sylvian fissure meningioma without dural attachment

Sylvian fissure meningioma without dural attachment

Sylvian fissure meningiomas (SFMs) represent a rare subgroup of nondural-based tumors arising from the meningothelial cells within the arachnoid of the Sylvian fissure.

In 1938 Harvey Williams Cushing and Louise Eisenhardt reported two cases of this type of tumor named as “Deep Sylvian Meningiomas” 1).


The reported adult SFMs patients are young (mean age of 34.95 ± 3.35 years; 95% CI [27.93–41.97]) with a M:F ratio of 1.22 (11/9) and in the pediatric population (mean age is 5.71 ± 1.61 years; 95% CI [1.76-9.66]; the M:F ratio is 2:1 (4/2 and 1 unknown). When comparing grade I and grade II lesions, there is no significant differences in terms of mean age (grade I: 26.87 ± 3.90 years; vs grade II 24.33 ± 7.01 years; t-test p > 0.05), gender (grade I M:F ratio – 1.2 [12/10] versus grade II M:F ratio – 5 [5/1)]), clinical presentation (seizures is the most common presentation in both groups – grade 1 – 74% (17/23) and grade II – 67% (4/6)] and extent of resection (total resection in grade 1 – 65% [1/23] and total resection in grade II – 50% [3/6].

Only six atypical WHO grade II SFMs have been previously described 2).

Clinical features

They usually manifest with seizures and display the same radiological features of meningiomas in other locations.

Differential diagnosis

SFMs are rare entities and it is important to differentiate them from the sphenoid wing meningiomas. These are attached to the dura overlying the sphenoid wings, are usually associated with hyperostosis and they displace the MCA backwards as they grow, while the SFMs do not have dural attachment, do not produce hyperostosis and grow inbetween the MCA branches 3).


Although the absence of dural attachment makes these tumors suitable for a complete resection, their anatomical relationships with the middle cerebral artery branches may impair its achievement.

In the case of recurrent meningioma, surgical resection and adjuvant radiation therapy could be effective for long-term control of the tumor. 4).

Case reports

Hong et al., presented a histologically regressed relapsed meningioma, which spontaneously regressed after subtotal resection. In the case of recurrent meningioma, surgical resection and adjuvant radiation therapy could be effective for long-term control of the tumor. 5).

Donovan and Thavapalan, report two additional cases of sylvian fissure meningioma without dural attachment and one case of perisylvian meningioangiomatosis in the medial temporal lobe. All three patients presented with complex partial seizures, but the diagnosis was delayed in each case because the symptoms were misinterpreted to be behavioral rather than epileptic. The seizures were eventually confirmed with electroencephalogram, and subsequent imaging showed enhancing masses within the sylvian fissure region that were at least partially calcified in all three cases. Each patient underwent craniotomy. In the first case, gross total resection was achieved, and in the second case, a small residual portion of tumor was densely calcified and adherent to the middle cerebral artery branches. Both of these were World Health Organization (WHO) grade I meningiomas. The third patient underwent biopsy and limited resection of meningioangiomatosis. No dural attachments were noted in any of the tumors, but one of the meningiomas was intraparenchymal in location, surrounding the sylvian fissure in both the frontal and temporal lobes, which has been described in only a small number of these cases previously. The patients underwent pre- and postsurgical neuropsychiatric testing and did not experience any significant cognitive deficits. At 10-year follow-up, the patient who had gross total resection of the tumor has had no recurrence and is seizure-free without anticonvulsant medications. The incompletely resected intraparenchymal meningioma in the second patient recurred after 5 years, however, and at repeat surgery was found to have transformed to a WHO grade II tumor. Radiation therapy was delivered and the tumor has been stable for 2 years, but the patient continues to have occasional seizures despite medication. The patient with meningioangiomatosis has had no further growth and has excellent control of seizures but remains on medication. 6).

A heterogeneous contrast-enhanced mass in the right sylvian fissure of a 10-year-old boy with a 3-year history of epilepsy was identified via magnetic resonance imaging. The patient underwent partial surgical resection because the tumor was hard and contained numerous perforators arising from the right middle cerebral artery. The tumor was histologically diagnosed as sclerosing meningioma. Twelve months after surgery, the patient was asymptomatic and did not require any additional therapies. This case is the first report of a sclerosing meningioma arising in the deep sylvian fissure 7).

Aras et al., reported staged surgery for sylvian fissure meningiomas without dural attachment in two cases 8).

In 2013 a Deep Sylvian Meningioma in a 43-Year-Old Man 9).

Ma et al., reported a case of sylvian fissure atypical meningioma with a 20-year history. The tumor was excised subtotally, thereafter a postoperative radiation therapy was done. The patient had a favorable outcome during the two-year follow-up 10).

Miyahara et al., reported a 34-year-old female with an 8-year history of temporal lobe epilepsy. Magnetic resonance imaging showed a multilobular, well-demarcated and homogeneous tumorous lesion of 5 cm in diameter deep in the left sylvian fissure. Intraoperative findings revealed that the tumor was mainly in the left insular region without dural attachment and strongly adhered to the left middle cerebral artery and its perforators. The histopathological diagnosis was transitional meningioma without malignancy 11).

Cecchi et al., described an atypical sylvian fissure meningioma in a 23-year-old male with a brief history of headache and mild hemiparesis 12).

A 6-year-old boy presented with seizures. Computed tomography and magnetic resonance imaging showed a large enhancing mass in the left temporo-parietal region.

He underwent left temporo-parietal craniotomy and total excision of the lesion. At surgery, there was no dural attachment, and the tumor was mainly in the posterior part of left sylvian fissure. The biopsy was reported as WHO grade I meningioma.

At 4-year follow-up, he was asymptomatic, and there was no tumor recurrence. 13).

Brain CT scan performed on a 73-year-old woman on admission for non-specific symptoms revealed. a heterodense temporoparietal mass which was demonstrated on carotid angiography as being fed by the middle cerebral artery. Preoperatively, a glioma was considered as being most probable because of its radiological features. The mass, which at surgery was found to be located in the sylvian fissure, was histologically confirmed to be a meningotheliomatous meningioma with fibroblastic component 14).

In 2005 McIver et al., first reported case of a chordoid meningioma without dural attachment arising in the sylvian fissure.

The patient presented with a generalized seizure. A heterogeneously enhancing right frontotemporal mass was identified on magnetic resonance imaging of the brain.

The patient underwent a failed stereotactic biopsy attempt elsewhere. The tumor was ultimately resected using standard microsurgical techniques.15).

A 35-year-old male. The patient visited the hospital because of a 10-year history of simple partial seizures. Magnetic resonance imaging revealed a 3.5-cm, well-circumscribed, homogenously enhanced, circular mass without dural attachments in the left insular region. The tumor was not stained on angiogram. The tumor was located in the extra-axial space of the sylvian fissure without any dural attachment, and was strongly attached to the middle cerebral artery. The tumor was excised, and a histological diagnosis of a transitional meningioma without a malignancy was made 16).

In 2002 a Pediatric sylvian fissure meningioma 17).

A one-year-eight-month old child who experienced the onset of a convulsive seizure. He had no neurological deficit and no developmental disorders. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a large left temporal tumor which was well enhanced and without dural attachment. Angiography revealed a slight tumor stain in the left Sylvian fissure supplied by branches of the internal carotid artery. Total removal of the tumor was performed, and they found that the tumor had no dural attachment, but was strongly attached to the M2 segment of the left middle cerebral artery. Pathological examinations revealed it to be a fibrous meningioma without malignancy 18).

Cooper et al., reported in 1997 a case in a 4-year-old child 19).

A 62-year-old woman was admitted because of one year history of temporal lobe epilepsy. She had no neurological deficit except for EEG abnormality. CT scans showed a small calcified mass in the left temporal lobe adjacent to the sylvian fissure with no enhancement by contrast medium. The mass was low-intense in both T1- and T2-weighted MR images. The T1-weighted image after the infusion of gadolinium revealed enhancement of the middle cerebral artery adjacent to the mass, similar to dural tail sign. Left external carotid angiography did not show any tumor stain nor the dilatation of the middle meningeal artery. Left internal carotid angiography disclosed enlarged middle cerebral artery without tumor stain. A left frontotemporal craniotomy was performed and the mass was totally removed. The tumor was located deep in sylvian fissure without any connection to the dura or ventricular system, which was firmly adherent to the middle cerebral artery. The histological examination of the surgical specimen revealed a psammomatous meningioma MR findings in deep sylvian meningioma was described 20).

Mori et al., reported a 12-year-old boy who has been suffering from severe headache for a month. Neurological examination was normal. CT scan and MR images showed a well-enhanced 7 cm mass lesion with small cysts, located in the left sylvian fissure. Peritumoral edema was slight and the midline structures were minimally shifted in spite of its large size. A fronto-temporal craniotomy was made and the tumor was grossly totally removed. The tumor had no dural attachment and existed in the left sylvian fissure, involving the middle cerebral artery and its branches. The histological diagnosis was transitional meningioma without malignancy. The postoperative course was uneventful except for transient mild left oculomotor palsy for several days. He is doing well now one year after the surgery and follow-up MR images showed no recurrence. Intracranial meningioma is rare in children. According to the literature, meningioma in children is slightly more frequent in males. There is a higher incidence of lack of dural attachment and cystic tumors than in adults. Deep sylvian meningioma without dural attachment is also very rare. Including our case, 13 cases of deep sylvian meningioma were reported in the literature. Four of them were under 20 years old. We report this case in detail with other cases reported previously. 21).

Chiocca et al., reported a deep sylvian fissure meningioma without dural attachments in the right hemisphere of an adult patient. The patient initially presented with simple partial seizures. Magnetic resonance imaging revealed a contrast-enhancing circular mass in the superior aspect of the insular region, deep to the inferior parietal lobule. Surgical exploration confirmed the absence of dural attachments. Microscopically, the tumor was found to be a sparsely cellular meningioma with an extensive collagenous matrix 22).

Graziani et al., in 1992 reported a case 23).

Cho et al., published a 2-year-old boy with a deep sylvian meningioma 24).

Silbergeld et al., a Sylvian fissure meningioma in a 4-year-old female 25).

In 1986 a 34-year-old Japanese woman, who had experienced several episodes of fainting attacks since 19 years old, was admitted to our hospital on March 22, 1983. Her plain skull roentgenogram showed abnormal calcification in her left fronto-temporal region. CT scan demonstrated clear-marginal high density mass in the left sylvian fissure which was homogeneously enhanced after administration of contrast medium. Left carotid angiogram showed intrasylvian mass with small tumor stain in late arterial phase, but external carotid artery had no concern with this tumor. On March 30, left fronto-temporal craniotomy was performed. The tumor was located in the extra-axial space of the sylvian fissure without any attachment to the dura mater or to the choroid plexus of the ventricles. This hard tumor, 70 grams in its weight, was successfully removed. It was histologically diagnosed fibroblastic meningioma. The patient was discharged without any neurological deficits. Twenty-four cases of meningiomas not attached to the dura mater or to choroid plexus could be reviewed from the literature. This type of meningioma is occasionally called “deep sylvian meningioma”, but in some reports the tumors developed far from sylvian fissure. And even in the cases in which the tumors were reported to be located in the sylvian fissure, macroscopic space where tumors developed was various. The clinical features, diagnosis, and surgical management of this tumor were also discussed in the report 26).

Okamoto et al., published a 35-year-old woman who was precisely diagnosed preoperatively with the aid of computed tomography and stereoscopic cerebral angiography. On reviewing the literature, it appears to be the first case that has been accurately diagnosed preoperatively and successfully treated by a total excision without serious complication 27).

Tsuchida et al., in 1981 published the only one of deep sylvian meningioma in the whole series of 181 intracranial meningiomas and probably the twentieth case reported so far in the literature. 28).

Saito et al., reported a case of 31-year-old female who had episodes of fainting attack. She had no significant neurological deficit but had EEG abnormality. Carotid angiography showed a tumor stain, ca. 1.7 cm in diameter, near the right insula. CT scan also revealed a high density area at the same site. At the time of operation, a small tumor located deeply in the right sylvian fissure was found out and successfully removed. Histologically, this tumor was diagnosed as a meningioma having some typical psammomatous features 29).

Mori et al., reported a case of “deep sylvian meningioma” 30).

Barcia-Goyanes and Calvo-Garra described a case in 1953 31),



Cushing H, Eisenhardt L: Meningiomas: Their Classification, Regional Behavior, Life History, and Surgical End Results. Springfield, Charles C. Thomas, 1938.

Brogna C, Lavrador JP, Patel S, Ribas EC, Aizpurua M, Vergani F, Ashkan K, Bhangoo R. Grade II Sylvian fissure meningiomas without dural attachment: case report and review of the literature. CNS Oncol. 2018 Dec 1;7(4):CNS20. doi: 10.2217/cns-2018-0004. Epub 2018 Oct 2. PubMed PMID: 30277091; PubMed Central PMCID: PMC6331700.

Cecchi PC, Campello M, Rizzo P, Mair K, Schwarz A. Atypical meningioma of the sylvian fissure. J Clin Neurosci. 2009 Sep;16(9):1234-9. doi: 10.1016/j.jocn.2008.10.027. Epub 2009 Jun 3. PubMed PMID: 19497747.
4) , 5)

Hong S, Usami K, Hirokawa D, Ogiwara H. Pediatric meningiomas: a report of 5 cases and review of literature. Childs Nerv Syst. 2019 Apr 18. doi: 10.1007/s00381-019-04142-y. [Epub ahead of print] PubMed PMID: 31001646.

Donovan DJ, Thavapalan V. Pediatric Meningeal Tumors of the Sylvian Fissure Region without Dural Attachment: A Series of Three Patients and Review of the Literature. Surg J (N Y). 2016 May 26;2(2):e31-e36. doi: 10.1055/s-0036-1584166. eCollection 2016 Apr. Review. PubMed PMID: 28824987; PubMed Central PMCID: PMC5553465.

Fukushima S, Narita Y, Yonezawa M, Ohno M, Arita H, Miyakita Y, Ichimura K, Yoshida A, Shibui S. Short communication: sclerosing meningioma in the deep sylvian fissure. Brain Tumor Pathol. 2014 Oct;31(4):289-92. doi: 10.1007/s10014-013-0167-8. Epub 2013 Oct 19. PubMed PMID: 24141724.

Aras Y, Akcakaya MO, Aydoseli A, Izgi N. Staged surgery for sylvian fissure meningiomas without dural attachment: report of two cases. Clin Neurol Neurosurg. 2013 Aug;115(8):1527-9. doi: 10.1016/j.clineuro.2012.12.010. Epub 2013 Jan 3. PubMed PMID: 23290420.

Kim JY, Lee EJ, Chang HW, et al. Deep Sylvian meningioma in a 43-year-old man: a case report. J. Korean Soc. Magn. Reson. Med. 2013;17(4):308–311

Ma L, Xiao SY, Zhang YK. Atypical meningioma of sylvian fissure with a 20-year history: a rare case report. Neurol Sci. 2012 Feb;33(1):143-5. doi: 10.1007/s10072-011-0637-x. Epub 2011 May 27. PubMed PMID: 21617950.

Miyahara K, Ichikawa T, Yagishita S, Mukaihara S, Okada T, Kaku S, Tanino S, Uriu Y, Fujitsu K, Niino H. [Deep sylvian meningioma without dural attachment: a case report]. No Shinkei Geka. 2011 Nov;39(11):1067-72. Review. Japanese. PubMed PMID: 22036818.

Cecchi PC, Campello M, Rizzo P, Mair K, Schwarz A. Atypical meningioma of the sylvian fissure. J Clin Neurosci. 2009 Sep;16(9):1234-9. doi: 10.1016/j.jocn.2008.10.027. Epub 2009 Jun 3. PubMed PMID: 19497747.

Samson Sujit Kumar G, Rajshekhar V. Deep sylvian meningioma: a case report and review of literature. Childs Nerv Syst. 2009 Jan;25(1):129-32. doi: 10.1007/s00381-008-0686-5. Epub 2008 Aug 19. Review. PubMed PMID: 18712398.

Eghwrudjakpor PO, Mori K. Sylvian cleft meningioma: surgical approach and postoperative morbidity. Niger J Med. 2006 Oct-Dec;15(4):437-40. PubMed PMID: 17111734.

McIver JI, Scheithauer BW, Atkinson JL. Deep Sylvian fissure chordoid meningioma: case report. Neurosurgery. 2005 Nov;57(5):E1064; discussion E1064. PubMed PMID: 16284544.

Chang JH, Kim JA, Chang JW, Park YG, Kim TS. Sylvian meningioma without dural attachment in an adult. J Neurooncol. 2005 Aug;74(1):43-5. PubMed PMID: 16078106.

Kaplan SS, Ojemann JG, Park TS. Pediatric sylvian fissure meningioma. Pediatr Neurosurg. 2002 May;36(5):275-6. PubMed PMID: 12053048.

Mitsuyama T, Kasuya H, Kubo O, Hirasawa K, Hori T. [Left Sylvian fissure meningioma in a one-year-eight-month old child]. No Shinkei Geka. 2000 May;28(5):459-64. Review. Japanese. PubMed PMID: 10806631.

Cooper JR, Marshman LA, Smith CM, Powell T. Case report: Sylvian fissure meningioma without dural attachment in a 4-year-old child. Clin Radiol. 1997 Nov;52(11):874-6. PubMed PMID: 9392468.

Matsumoto S, Yamamoto T, Ban S, Sato S, Shingu T, Yoshida S, Tokuno T, Nakazawa K, Saiwai S, Shirane H. [A case of deep sylvian meningioma presenting temporal lobe epilepsy]. No To Shinkei. 1995 May;47(5):503-8. Japanese. PubMed PMID: 7786628.

Mori Y, Shibuya M, Sugita K, Nagasaka T. [Deep sylvian meningioma: a case report of a child]. No Shinkei Geka. 1994 Dec;22(12):1147-51. Review. Japanese. PubMed PMID: 7845511.

Chiocca EA, Boviatsis EJ, Westmark RM, Short MP, Richardson EP, Zervas NT. Deep sylvian fissure meningioma without dural attachment in an adult: case report. Neurosurgery. 1994 Nov;35(5):944-6; discussion 946. Review. PubMed PMID: 7838346.

Graziani N, Donnet A, Vincentelli F, Dechambenoit G, Grisoli F. [Deep sylvian meningioma. Apropos of a case. Review of the literature]. Neurochirurgie. 1992;38(3):179-82. Review. French. PubMed PMID: 1461337.

Cho BK, Wang KC, Chang KH, Chi JG. Deep sylvian meningioma in a child. Childs Nerv Syst. 1990 Jun;6(4):228-30. PubMed PMID: 2383879.

Silbergeld D, Berger M, Griffin B. Sylvian fissure meningioma in a child: case report and review of the literature. Pediatr Neurosci. 1988;14(1):50-3. PubMed PMID: 3217285.

Hirao M, Oka N, Hirashima Y, Horie Y, Takaku A. [Deep sylvian meningioma: case report and review of the literature]. No Shinkei Geka. 1986 Nov;14(12):1471-8. Japanese. PubMed PMID: 3808209.

Okamoto S, Handa H, Yamashita J, Tokuriki Y. Deep Sylvian meningiomas. Surg Neurol. 1985 Mar;23(3):303-8. PubMed PMID: 3975816.

Tsuchida T, Ito J, Sekiguchi K, Honda H, Ueki K. [A case of deep sylvian meningioma with intracerebral hematoma (author’s transl)]. No Shinkei Geka. 1981;9(3):395-400. Japanese. PubMed PMID: 7242824.

Saito A, Mizuno Y, Adachi Y, Itoh T. [Deep Sylvian psammomeningioma, report of a case (author’s transl)]. No To Shinkei. 1979 Jan;31(1):79-83. Japanese. PubMed PMID: 426936.

Mori S, Ishihara H, Sogabe T, Kodama Y, Hibino H. [A case of deep sylvian meningioma (author’s transl)]. No Shinkei Geka. 1977 Apr;5(4):385-92. Japanese. PubMed PMID: 558541.

Barcia-Goyanes JJ, Calvo-Garra W. Meningiomas without dural attachment. Acta Neurochir. 1953;3:241–247.

Update: Sylvian fissure arachnoid cyst

A Sylvian fissure intracranial arachnoid cyst (SAC) is a well-recognized location for an intracranial arachnoid cyst in the pediatric population.
Arachnoid cysts situated in the middle cranial fossa constitute the largest group of this type of lesion.


The Galassi classification of middle cranial fossa arachnoid cysts is used to classify arachnoid cysts in the middle cranial fossa, which account for 50-60% of all arachnoid cysts.
Galassi et al published this classification in 1982, and at the time of writing (November 2016) it remains the most widely used system for these lesions.
It is a simple system, using the size and degree of displacement of adjacent brain to divide cysts three types. The size also correlates with the ease with which the cyst communicates with the subarachnoid space as discerned on CT cisternography or phase contrast MRI.

type I small, spindle-shaped limited to the anterior portion of the middle cranial fossa, below the spenoid ridge free communication of subarachnoid space
type II superior extent along sylvian fissure displacement of the temporal lobe slow communication with subarachnoid space
type III large, fills the whole middle cranial fossa displacement of not only the temporal lobe but also the frontal and parietal lobes often results in midline shift little communication with subarachnoid space

Clinical features

Intracranial sylvian arachnoid cysts are often asymptomatic lesions.

(a) Axial CT scan showing a left sylvian fissure arachnoid cyst. (b) Complete resolution after excision and marsupialization.


Sylvian arachnoid cysts pose considerable management dilemmas. Surgical options include cyst fenestration, either endoscopically or microsurgically, and cystoperitoneal shunt.
The option of the mere clinical observation was chosen by the majority of surgeons in case of asymptomatic clinical discovery. On the other hand, a constantly high percentage of participants suggested direct surgical treatment based on clinical manifestations or as a preventive measure justified by the risk of spontaneous or traumatic intracranial bleeding. The only diagnostic investigation result which significantly influenced the surgical indication was a localizing electroencephalography, if the child presented with seizures. The result is that in most cases the surgical indication was based on a specific clinical manifestations and laboratory data. Craniotomy and arachnoid cyst marsupialization represented the preferred surgical option (66.6%), 28.8% of the participants suggesting pure or assisted endoscopic cyst marsupialization as primary surgical procedure. Cyst shunting was suggested by only three centers 2).
For those cysts, which can rupture and be accompanied by a subdural hygroma or subdural hematoma, several treatment modalities have been reported.
A study demonstrated efficacy in a predominantly endoscopically treated patient cohort with Sylvian fissure arachnoid cysts, as indicated by improvement of clinical symptoms and diminished radiological SAC volume after treatment 3)


it sometimes leads to subdural or intracystic hemorrhage without major trauma. The reason of easy bleeding of the AC is not fully understood.
One of the rare complications after rapid decompression of the arachnoid cysts is haemorrhage in the surrounding brain as well as in remote areas.
Long-standing asymptomatic sylvian arachnoid cysts may suddenly produce severe unilateral visual deficits if the cyst erodes the lateral orbital wall. These deficits may rapidly revert to normal if surgical action is not delayed. If surveillance MRIs of sylvian arachnoid cysts show a narrowing of the conus diameter compared to the contralateral side, a yearly ophthalmological surveillance examination seems to be warranted in else wise asymptomatic patients 4).

Case series

A retrospective review of the database of operative procedures revealed 24 procedures (20 endoscopic and 4 microsurgical procedures) to fenestrate a Sylvian fissure arachnoid cyst (SAC) at university hospitals in Berlin, Germany and Tokyo, Japan.
With the applied technique, a reduction of SAC volume of more than 10% was achieved in 83.3% of all patients. The median volume of SACs (n = 24) was significantly reduced from 83.5 mL (range 21-509 mL) preoperatively to 45.5 mL (range 8.4-261 mL; P < 0.01) after 3.5 months and to 29.0 mL (range 0-266 mL; P < 0.01) after 15 months. In children (n = 8) with a ruptured SAC the combined extraaxial volume of a SAC and accompanying hygroma/hematoma was reduced from 166 mL (range 111-291 mL) before surgery to 127 mL (range 87-329 mL) after 2 months and to 77 mL (range 25-140 mL; P < 0.05) after 11 months. Acute clinical symptoms were generally resolved postoperatively; headaches were resolved or improved in 75%. A significant association of resolution or improvement of headaches and volume reduction was demonstrated.
The study demonstrated efficacy in a predominantly endoscopically treated patient cohort with Sylvian fissure arachnoid cysts, as indicated by improvement of clinical symptoms and diminished radiological SAC volume after treatment 5).

Case reports


A case of multiple remote-site intra-parenchymal haemorrhage as a rare complication after surgical decompression of a sylvian fissure arachnoid cyst 6).


Lohani et al., present the case of an 11-year-old boy who presented after a week of progressive and severe back pain radiating to the back of his thighs. Imaging revealed a spinal subdural blood collection at the L4-S1 level. This finding prompted further cephalad imaging of the spine and the brain, which revealed a sylvian fissure arachnoid cyst with intracystic hemorrhage and frontoparietal subdural hematoma. The child did not have headache at this time, although he had experienced chronic headaches since the age of 4 years. He was treated with a course of oral steroids, which immediately relieved his back and leg pain. Subsequent imaging showed resolution of the cranial and spinal subdural blood collections and diminished size of the arachnoid cyst. No surgical treatment was necessary 7).

Upadhyaya et al. report a case of a sylvian cistern arachnoid cyst presenting with precocious puberty in a 3-year-old girl. The child recovered following a cystoperitoneal shunt. The mass effect of the arachnoid cyst upon the hypothalamus was, at least in part, responsible for the development of precocious puberty. To the best of the knowledge, this is the 1st case of a sylvian cistern arachnoid cyst presenting with precocious puberty. The role of surgical decompression of the cyst is also discussed 8).

Prokopienko et al., report the case of a 36-year-old woman with a Sylvian fissure arachnoid cyst, which diminished after head trauma and minor hemorrhage into the cyst. They discuss the relationship between the cyst volume reduction and the head trauma to determine the main mechanism of this self-healing process 9).


Intraparenchymal hemorrhage after surgical decompression of a Sylvian fissure arachnoid cyst 10).


A case of brain stem hemorrhage after decompression of a sylvian fissure arachnoid cyst has been reported 11).

1) Galassi E, Tognetti F, Gaist G, Fagioli L, Frank F, Frank G. CT scan and metrizamide CT cisternography in arachnoid cysts of the middle cranial fossa: classification and pathophysiological aspects. Surg Neurol. 1982 May;17(5):363-9. PubMed PMID: 7089853.
2) Tamburrini G, Dal Fabbro M, Di Rocco C. Sylvian fissure arachnoid cysts: a survey on their diagnostic workout and practical management. Childs Nerv Syst. 2008 May;24(5):593-604. doi: 10.1007/s00381-008-0585-9. Erratum in: Childs Nerv Syst. 2008 May;24(5):635. Del Fabbro, Mateus [corrected to Dal Fabbro, Mateus]. PubMed PMID: 18305944.
3) Schulz M, Kimura T, Akiyama O, Shimoji K, Spors B, Miyajima M, Thomale UW. Endoscopic and Microsurgical Treatment of Sylvian Fissure Arachnoid Cysts-Clinical and Radiological Outcome. World Neurosurg. 2015 Mar 25. pii: S1878-8750(15)00293-4. doi: 10.1016/j.wneu.2015.03.026. [Epub ahead of print] PubMed PMID: 25818148.
4) Kural C, Kullmann M, Weichselbaum A, Schuhmann MU. Congenital left temporal large arachnoid cyst causing intraorbital optic nerve damage in the second decade of life. Childs Nerv Syst. 2015 Aug 9. [Epub ahead of print] PubMed PMID: 26255149.
5) Schulz M, Kimura T, Akiyama O, Shimoji K, Spors B, Miyajima M, Thomale UW. Endoscopic and Microsurgical Treatment of Sylvian Fissure Arachnoid Cysts-Clinical and Radiological Outcome. World Neurosurg. 2015 Aug;84(2):327-36. doi: 10.1016/j.wneu.2015.03.026. PubMed PMID: 25818148.
6) Ramachandran GM, Nair RP, Kongwad LI, Shanthakumar G. Rapid Brain Shift with Remote-Site Haemorrhage after Arachnoid Cyst Excision: Treatment Dilemmas. Pediatr Neurosurg. 2016 Dec 3. [Epub ahead of print] PubMed PMID: 27915350.
7) Lohani S, Robertson RL, Proctor MR. Ruptured temporal lobe arachnoid cyst presenting with severe back pain. J Neurosurg Pediatr. 2013 Sep;12(3):281-3. doi: 10.3171/2013.6.PEDS13122. PubMed PMID: 23829378.
8) Upadhyaya S, Nair R, Kumar V, Nayal B, Shetty A. Sylvian cistern arachnoid cyst – a rare cause of precocious puberty. Pediatr Neurosurg. 2013;49(6):365-8. doi: 10.1159/000368323. Epub 2014 Nov 21. PubMed PMID: 25428575.
9) Prokopienko M, Kunert P, Marchel A. Unusual volume reduction of Galassi grade III arachnoid cyst following head trauma. J Neurol Surg A Cent Eur Neurosurg. 2013 Dec;74 Suppl 1:e198-202. doi: 10.1055/s-0033-1342931. PubMed PMID: 23696293.
10) Esmaeeli B, Eftekhar B. Intraparenchymal hemorrhage after surgical decompression of a Sylvian fissure arachnoid cyst. Neurol India. 2006 Sep;54(3):320-1. PubMed PMID: 16936408.
11) Borges G, Fernandes YB, Gallani NR. [Brainstem hemorrhage after surgical removal of arachnoid cyst of the Sylvian fissure: A case report]. Arq Neuropsiquiatr 1995;53:825-30.

Sylvian fissure

Sylvian fissure

The lateral sulcus also called Sylvian fissure (SyF) or lateral fissure is one of the most prominent structures of the brain (the fissure separating the temporal lobe from the parietal lobe and frontal lobes).

Sylvian fissure dissection is an essential microneurosurgical skill for neurosurgeons. The safe and accurate opening of the sylvian fissure is desirable for a good prognosis.

The central sulcus joins the Sylvian fissure in only 2 % of cases.

The Sylvian fissure terminates in the supramarginal gyrus (Brodmann area 40).


Approximated by a line connecting the lateral canthus to the point 3/4 of the way posterior along the arc running over convexity from nasion to inion (T-H lines).

The frontotemporal, so-called pterional approach has evolved with the contribution of many neurosurgeons over the past century. It has stood the test of time and has been the most commonly used transcranial approach in neurosurgery. In its current form, drilling the sphenoid wingas far down as the superior orbital fissure with or without the removal of the anterior clinoid process, thinning the orbital roof, and opening the Sylvian fissure and basal cisterns are the hallmarks of this approach.

The bone flap has been removed and the dura mater has been opened as a flap pediculated towards the greater sphenoid wing previously roungered to improve parasellar visualization. Sylvian fissure, Inferior frontal gyrus, Superior temporal gyrus and Middle temporal gyrus are exposed. Three pars of parasylvian inferior frontal gyrus must be distinguished: pars orbitalis (pOr) in relation to the orbital roof; pars triangularis (pT) the widest area of sylvian fissure (good place for start opening of sylvian fissure); pars opercularis (pOp) where Broca’s Area is located.


The sylvian fissure extends from the basal to the lateral surface of the brain and presents 2 compartments on each surface,

1 superficial (temporal stem and its ramii) and 1 deep (anterior and lateral operculoinsular compartments). The temporal operculum is in opposition to the frontal and parietal opercula (planum polare versus inferior frontal and precentral gyri, Heschl’s versus postcentral gyri, planum temporale versus supramarginal gyrus). The inferior frontal, precentral, and postcentral gyri cover the anterior, middle, and posterior thirds of the lateral surface of the insula, respectively. The pars triangularis covers the apex of the insula, located immediately distal to the genu of the middle cerebral artery. The clinical application of the anatomic information presented in the article of Wen et al. is in angiography, middle cerebral artery aneurysm surgery, insular resection, frontobasal resection, and amygdalohippocampectomy, and hemispherotomy 1).


The SyF is divided into a proximal segment and a distal segment separated by the anterior sylvian point (ASP).

It is the single most identifiable feature of the superolateral face of the brain, and together with the underlying sylvian cistern it constitutes the most frequently used microneurosurgical corridor because of the high proportion of intracranial lesions that are accessible through its opening 2).

The lateral sulcus divides both the frontal lobe and parietal lobe above from the temporal lobe below. It is in both hemispheres of the brain but is longer in the left hemisphere in most people. The lateral sulcus is one of the earliest-developing sulci of the human brain. It first appears around the fourteenth gestational week.

The sylvian fissure or lateral sulcus is the most identifiable feature of the superolateral brain surface and constitutes the main microneurosurgical corridor, given the high frequency of approachable intracranial lesions through this route.

In their original description of the microsurgical anatomy of the subarachnoid cisterns in 1976, Yasargil, et al., 3) emphasized the importance of the SyF, which then became the main microneurosurgical corridor to the base of the brain. In later publications Yasargil, et al., described in detail the microanatomy of this fissure and its underlying cistern 4) 5) 6) and the technique of its opening.

The opening of the fissure at the level of the anterior sylvian point (ASP) shows very soon the insular apex. The limen insula and the middle cerebral artery bifurcation are a little bit deeper and 1-2 cm. anteriorly. The opening of the sylvan fissure posteriorly to the ASP exposes the insula and the opening anteriorly leads to the suprasellar cisterns. The distance between the ASP and the IRP along the SF is 2.3 cm.


The lateral sulcus has a number of side branches. Two of the most prominent and most regularly found are the ascending (also called vertical) ramus and the horizontal ramus of the lateral fissure, which subdivide the inferior frontal gyrus. The lateral sulcus also contains the transverse temporal gyri, which are part of the primary and below the surface auditory cortex.

Partly due to a phenomenon called Yakovlevian torque, the lateral sulcus is often longer and less curved on the left hemisphere than on the right.

It is also located near Sylvian Point.

The area lying around the Sylvian fissure is often referred to as the perisylvian cortex. The human secondary somatosensory cortex (S2, SII) is a functionally-defined region of cortex in the parietal operculum on the ceiling of the lateral sulcus.

Yasargil divides the SyF into a proximal segment (stem, sphenoidal, anterior ramus) and a distal segment (lateral, posterior ramus) separated by the sylvian point 7) 8). which is located beneath the triangular part of the inferior frontal gyrus (IFG).

The horizontal and the anterior ascending branches of the SyF that delineate the triangular part of the IFG arise at the sylvian point 9).


Yasargil described four different types of intraoperatively observed anatomical sylvian fissure (SF) variants.

Category I is a straight wide SF, II a straight narrow SF, III a herniated frontal lobe into the SF and IV is a herniated temporal lobe into the SF. 10).

The SF categories used in the present work are based on the Yasargil classification with slight modifications since we categorized the SF on cranial computed tomography (CCT) scans and not anatomically.


Insular gliomas represent a unique surgical challenge due to the complex anatomy and nearby vascular elements associated within the Sylvian fissure. For certain tumors, the transsylvian approach provides an effective technique for achieving maximal safe resection.

The goal of the manuscript and video of Safaee et al., are to present and discuss the surgical nuances and appropriate application of splitting the Sylvian fissure. The hope is that this video highlights the safety and efficacy of the transsylvian approach for appropriately selected insular gliomas 11).




Wen HT, Rhoton AL Jr, de Oliveira E, Castro LH, Figueiredo EG, Teixeira MJ. Microsurgical anatomy of the temporal lobe: part 2–sylvian fissure region and its clinical application. Neurosurgery. 2009 Dec;65(6 Suppl):1-35; discussion 36. doi: 10.1227/01.NEU.0000336314.20759.85. PubMed PMID: 19934983.

Ribas GC, Ribas EC, Rodrigues CJ. The anterior sylvian point and the suprasylvian operculum. Neurosurg Focus. 2005 Jun 15;18(6B):E2. PubMed PMID: 16048297.

Yasargil MG, Kasdaglis K, Jain KK, et al: Anatomical observations of the subarachnoid cisterns of the brain during surgery. J Neurosurg 44:298–302, 1976

Yasargil MG: Microneurosurgery. Stuttgart: Georg Thieme, 1984, Vol I

Yasargil MG: Microneurosurgery. Stuttgart: Georg Thieme, 1994, Vol IV
6) , 8)

Yasargil MG, Krisht AF, Türe U, et al: Microsurgery of insular gliomas: Part I, II, IV. Contemporary Neurosurgery 24:(11):1–8; (13):1–6; (14):1–8, 2002

Türe U, Yasargil DCH, Al-Mefty O, et al: Topographic anatomy of the insular region. J Neurosurg 90:720–733, 1999

Ono M, Kubik S, Abernathey CD: Atlas of Cerebral Sulci. Stuttgart: Thieme, 1990

Yasargil MG. Stuttgart: Thieme Publishers; 1984. Operative anatomy, in Microneurosurgery; pp. 252–90.

Safaee MM, Englot DJ, Han SJ, Lawton MT, Berger MS. The transsylvian approach for resection of insular gliomas: technical nuances of splitting the Sylvian fissure. J Neurooncol. 2016 Nov;130(2):283-287. Review. PubMed PMID: 27294356.
WhatsApp WhatsApp us
%d bloggers like this: