Pigmented variant of pleomorphic xanthoastrocytoma

Pigmented variant of pleomorphic xanthoastrocytoma

Pleomorphic xanthoastrocytoma (PXA) is an uncommon, long-term epilepsy associated tumor of young adults. Its pigmented variant is exceedingly rare, with only six reported cases 1).


Poyuran et al. reported the sixth case of pigmented PXA in a 24-year-old lady presenting with long-standing seizures. The MRI revealed a solid cystic lesion located in the right medial temporal lobe. Histopathologically, the superficially located tumor showed typical features of PXA with melanin-laden astrocytic component and was negative for V600E-mutant BRAF 2).


Gupta et al. reporteds a unique case of pleomorphic xanthoastrocytoma (PXA) in a 19-year-old male presenting with the chief complaint of seizures. On radiology, the tumor was located in the temporal lobe. It was cortically based and solid cystic in nature. Light microscopy showed pleomorphic large polygonal cells with inclusions, nuclear clustering, lipidization, and foamy cytoplasm intermingled with spindle cells arranged in sweeping pattern and focally containing cytoplasmic brownish black pigment. The pigment stained black with Fontana-Masson stain and bleached with potassium permanganate. Gomori silver stain showed reticulin fibers surrounding individual tumor cells as well as groups of cells. On immunohistochemistry, tumor cells were positive for GFAP, S-100 and focally for synaptophysin and CD34 but negative for HMB-45. CD34 revealed a specific membranous pattern around individual cells as well as groups of cells along the fibers replicating a reticulin pattern. The ultrastructural examination showed supporting melanosomes, thus confirming the melanin pigment. Sequencing for BRAF V600E showed a heterozygous mutation. This case provides further insight into the origin and pathogenesis of pigmented astrocytic tumor, additionally highlighting the characteristic CD34 staining pattern 3).


A 16-year-old male teenager presented with seizure and loss of consciousness for 20 min. Magnetic resonance imaging demonstrated a mass occupying the right medial temporal lobe. Histological examination revealed a non-pigmented area with spindle-shaped and large xanthomatous pleomorphic cells and a pigmented region with pigmented neoplastic cells with fascicular arrangement. Immunohistochemical studies showed the tumor was positive for GFAP and low index of Ki-67. Considering the patient’s history, clinical data and pathological findings, they rendered a pigmented pleomorphic xanthoastrocytoma 4).


A 15 year old male presented with hydrocephalus from a tectal mass obstructing the cerebral aqueduct and upper fourth ventricle. The solid-cystic partly enhancing mass proved to be a pigmented pleomorphic xanthoastrocytoma, the third such example reported. The lesion revealed typical features of a PXA with the unusual addition of intracytoplasmic melanin in select lesional cells. Melanin pigment production is uncommon in glial tumors and of uncertain significance. The present case is recurrence-free one year post-operatively 5).


A large suprasellar, partly cystic, contrast-enhancing tumor was resected from a 19-year-old woman who presented with bitemporal visual field defects and reduced visual acuity. Grossly, the tumor was brown and located in the subarachnoid space. Histologically, it was composed of spindle and pleomorphic cells, including giant tumor cells, with markedly pleomorphic nuclei. Reticulin fibers surrounded single cells and small groups of cells. Very few mitotic figures were found in the tumor, and no necrosis or microvascular proliferation was seen. The tumor thereby resembled a pleomorphic xanthoastrocytoma. Many of the tumor cells contained a dark-brown intracytoplasmic pigment, shown to be melanosomal melanin by ultrastructural examination. Immunohistochemical examination demonstrated that the pigment was present in glial tumor cells. Only four cases of pigmented astrocytic tumors have been published, none of these were suprasellar. The patient received fractionated radiotherapy with a total dose of 48.6 Gy 14 months after gross total removal of the tumor. She is alive without relapse after 12-year follow-up 6).


A 32-year-old man who presented with partial complex seizures. Radiologically, the mass was located in the medial temporal lobe and was solid and cystic. Microscopic examination revealed features of a pleomorphic xanthoastrocytoma with some heavily pigmented cells. The pigment was demonstrated to be melanosomal melanin, which was confirmed by special stains, immunohistochemistry, and electron microscopy 7).

References

1) , 2)

Poyuran R, Moudgil N, Arimappamagan A, Bharath RD, Mahadevan A. Pigmented variant of pleomorphic xanthoastrocytoma – A rare long-term epilepsy associated neoplasm. Indian J Pathol Microbiol. 2019 Jul-Sep;62(3):445-447. doi: 10.4103/IJPM.IJPM_723_18. PubMed PMID: 31361236.
3)

Gupta RK, Saran RK, Sharma MC, Srivastava AK, Garg L. Melanosomal melanin pigment in pleomorphic xanthoastrocytoma, evidence for neuronal-glial origin: A case report with review of the literature. Neuropathology. 2017 Apr;37(2):116-121. doi: 10.1111/neup.12344. Epub 2016 Sep 19. PubMed PMID: 27645472.
4)

Xiong J, Chu SG, Mao Y, Wang Y. Pigmented pleomorphic xanthoastrocytoma: a rare variant and literature review. Neuropathology. 2011 Feb;31(1):88-92. doi: 10.1111/j.1440-1789.2010.01132.x. Review. PubMed PMID: 20573030.
5)

Chapman EM, Ranger A, Lee DH, Hammond RR. A 15 year old boy with a posterior fossa tumor. Brain Pathol. 2009 Apr;19(2):349-52. doi: 10.1111/j.1750-3639.2009.00281.x. PubMed PMID: 19291005.
6)

Krossnes BK, Mella O, Wester K, Mørk SJ. Pigmented astrocytoma with suprasellar location: case report and literature review. Acta Neuropathol. 2004 Nov;108(5):461-6. Epub 2004 Sep 7. PubMed PMID: 15365722.
7)

Sharma MC, Arora R, Khanna N, Singh VP, Sarkar C. Pigmented pleomorphic xanthoastrocytoma: report of a rare case with review of the literature. Arch Pathol Lab Med. 2001 Jun;125(6):808-11. Review. PubMed PMID: 11371237.

Hydrocephalus Classification

Hydrocephalus Classification

There is no international consensus on the classification of hydrocephalus, and there are various systems based on the age of onset, cerebrospinal fluid dynamics and anatomical area of accumulation, the levels of cerebrospinal fluid pressure and the presence of symptoms.

However, no definitive classification exists comprehensively to cover the variety of these aspects.

Wu et al. proposed a classification Based on Ventricular Pressure 1).


Walter Edward Dandy first described the basic mechanism and classification of hydrocephalus as:

Obstructive hydrocephalus or Non Obstructive hydrocephalus.

Despite advances in understanding of the underlying process, current classification systems still rely upon Dandy’s classification scheme 2).


The aim of a study was to evaluate the diagnostic utility of three-dimensional sampling perfection with application optimized contrast using different flip angle evolution (3D SPACE) sequence and Susceptibility Weighted Imaging (SWI) in hydrocephalus and to propose a refined definition and classification of hydrocephalus with relevance to the selection of treatment option.

A prospective study of 109 patients with hydrocephalus was performed with magnetic resonance imaging (MRI) brain using standardized institutional sequences along with additional sequences 3D SPACE and SWI. The images were independently read by two senior neuroradiologists and the etiopathogenesis of hydrocephalus was arrived by consensus.

With conventional sequences, 46 out of 109 patients of hydrocephalus were diagnosed as obstructive of which 21 patients showed direct signs of obstruction and 25 showed indirect signs. In the remaining 63 patients of communicating hydrocephalus, cause could not be found out in 41 patients. Whereas with 3D SPACE sequence, 88 patients were diagnosed as obstructive hydrocephalus in which all of them showed direct signs of obstruction and 21 patients were diagnosed as communicating hydrocephalus. By including SWI, we found out hemorrhage causing intraventricular obstruction in three patients and hemorrhage at various sites in 24 other patients. With these findings, we have classified the hydrocephalus into communicating and noncommunicating, with latter divided into intraventricular and extraventricular obstruction, which is very well pertaining to the selection of surgical option.

Chellathurai et al., strongly suggest to include 3D SPACE and SWI sequences in the set of routine MRI sequences, as they are powerful diagnostic tools and offer complementary information regarding the precise evaluation of the etiopathogenesis of hydrocephalus and have an effective impact in selecting the mode of management 3).

Terms used

Acquired hydrocephalus

Adult hydrocephalus

Arrested hydrocephalus or Compensated hydrocephalus

Chronic hydrocephalus

Communicating hydrocephalus or Non obstructive hydrocephalus

Congenital hydrocephalus

External hydrocephalus

Focal hydrocephalus

Hydrocephalus Ex Vacuo

Idiopathic normal pressure hydrocephalus

Infantile hydrocephalus or Pediatric hydrocephalus.

Internal hydrocephalus

Non obstructive hydrocephalus or Communicating hydrocephalus

Normal pressure hydrocephalus for Idiopathic normal pressure hydrocephalus or Secondary normal pressure hydrocephalus.

Obstructive hydrocephalus.

Pediatric hydrocephalus or Infantile hydrocephalus

Secondary normal pressure hydrocephalus.

Unilateral hydrocephalus.


With the rare exception of hydrocephalus associated with overproduction of CSF in patients with choroid plexus papillomas (CPPs), all hydrocephalus is basically obstructive hydrocephalus. That the rare CPP causes hydrocephalus is not debated, but why it does so is the subject of some discussion. CPPs are known to lead to increases in the rate of CSF production and are known to cause hydrocephalus.

Normal CSF absorptive mechanisms can clear the amount of spinal fluid produced in the ventricular system at extremely high rates without producing ventriculomegaly. If CSF production and ICP increase substantially, ventricular size increases 4). When CSF flow is obstructed in the context of increased CSF production, there is a great tendency for ventriculomegaly or hydrocephalus to develop. CPPs, in themselves, can create the only pure form of communicating hydrocephalus. However, that these tumors tend to be large and to restrict CSF flow through the foramen of Monro or aqueduct of Sylvius, is more likely to account for the severity of hydrocephalus in this context 5).

When hydrocephalus is severe, especially in the very young, it may not be possible to define the point of CSF obstruction without introducing tracers into the CSF pathways. In patients treated early in life whose ventricles have become smaller with treatment, it is possible to determine the first site of obstruction to CSF flow on MRI or CT.

Patients with complex congenital anomalies such as hydrocephalus related to a Chiari II malformation and spina bifida often have multiple sites of obstruction 6) 7). It may not be possible to predict a second or downstream point of obstruction. In these patients, only one point may be obstructed or all of these sites may be restricted.

Based on a analyses from a mathematical modeling, of the work on the circuitry of CSF flow, and these potential sites of obstruction, Rekate et al., proposed a classification

It is generally assumed that endoscopic third ventriculostomy (ETV) is only effective for treating obstructive hydrocephalus, and many assume that obstructive hydrocephalus is synonymous with aqueductal stenosis. The growing number of reports on the efficacy of ETV for treating “communicating hydrocephalus” has generated considerable consternation 8).


The “Multi-categorical Hydrocephalus Classification” (Mc HC), was invented and developed to cover the entire aspects of hydrocephalus with all considerable classification items and categories.

Ten categories include “Mc HC” category I: onset (age, phase), II: cause, III: underlying lesion, IV: symptomatology, V: pathophysiology 1-CSF circulation, VI: pathophysiology 2-ICP dynamics, VII: chronology, VII: post-shunt, VIII: post-endoscopic third ventriculostomy, and X: others. From a 100-year search of publication related to the classification of hydrocephalus, 14 representative publications were reviewed and divided into the 10 categories.

The Baumkuchen classification graph made from the round o’clock classification demonstrated the historical tendency of deviation to the categories in pathophysiology, either CSF or ICP dynamics.

In the preliminary clinical application, it was concluded that “Mc HC” is extremely effective in expressing the individual state with various categories in the past and present condition or among the compatible cases of hydrocephalus along with the possible chronological change in the future 9).

References

1)

Wu X, Zang D, Wu X, Sun Y, Yu J, Hu J. Diagnosis and Management for Secondary Low- or Negative-Pressure Hydrocephalus and a New Hydrocephalus Classification Based on Ventricular Pressure. World Neurosurg. 2019 Jan 4. pii: S1878-8750(18)32946-2. doi: 10.1016/j.wneu.2018.12.123. [Epub ahead of print] PubMed PMID: 30611954.
2)

Dandy WE, Blackfan KD. Internal hydrocephalus: an experimental, clinical and pathological study. Am J Dis Child. 1914;8(6):406-482.
3)

Chellathurai A, Subbiah K, Abdul Ajis BN, Balasubramaniam S, Gnanasigamani S. Role of 3D SPACE sequence and susceptibility weighted imaging in the evaluation of hydrocephalus and treatment-oriented refined classification of hydrocephalus. Indian J Radiol Imaging. 2018 Oct-Dec;28(4):385-394. doi: 10.4103/ijri.IJRI_161_18. PubMed PMID: 30662197; PubMed Central PMCID: PMC6319109.
4) , 5)

Rekate HL, Erwood S, Brodkey JA, Chizeck HJ, Spear T, Ko W, Montague F. Etiology of ventriculomegaly in choroid plexus papilloma. Pediatr Neurosci. 1985;12:196–201.
6)

Rekate HL. Neurosurgical management of the newborn with spinal bifida. In: Rekate HL, editor. Comprehensive Management of Spina Bifida. Boca Raton, FL, CRC Press; 1991. pp. 1–20.
7)

Rekate HL. Neurosurgical mangement of the child with spinal bifida. In: Rekate HL, editor. Comprehensive Management of Spina Bifida. Boca Raton, FL, CRC Press; 1991. pp. 93–112.
8)

Rekate HL. Selecting patients for endoscopic third ventriculostomy. Neurosurg Clin N Am. 2004;15:39–49. doi: 10.1016/S1042-3680(03)00074-3.
9)

Oi S. Classification of hydrocephalus: critical analysis of classification categories and advantages of “Multi-categorical Hydrocephalus Classification” (Mc HC). Childs Nerv Syst. 2011 Oct;27(10):1523-33. doi: 10.1007/s00381-011-1542-6. Epub 2011 Sep 17. Review. PubMed PMID: 21928018.
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