Clear-cell ependymoma: A report of intracortical tumor with significant desmoplasia

RELA fusion-positive ependymoma accompanied by extensive desmoplasia: a case report

We report a case of 33-year-old Japanese male who presented with a headache and visual disturbances. Magnetic resonance imaging revealed a large tumor in the left frontal lobe, measuring 7 cm in diameter, which was diagnosed as supratentorial anaplastic ependymoma accompanied by extensive desmoplasia. The patient underwent a gross total resection. Histologically, the tumor cells had oval or short, spindle-shaped nuclei, and proliferating cells in perivascular pseudorosettes with anucleate zones and mitotic figures. Desmoplasia with abundant collagen fibers among the tumor cells was detected at numerous sites, and perinuclear dot- or ring-like immunoreactivity for epithelial membrane antigen was identified. Five years and six months after the initial procedure, a small recurrent tumor was identified at the removal site. The patient underwent a second total resection. The histology of the resected tumor showed decreased collagen production and more apparent anaplastic features as compared to those of the initial tumor. In addition to the histological findings, molecular examinations revealed ependymoma, RELA fusion positive. Although not commonly observed, this case suggests that desmoplasia could be associated with ependymomas, including RELA fusion-positive variant. Moreover, our findings indicate that high-grade ependymoma requires careful, long-term follow-up even if gross total resection is performed.

Prognostic Implications of Histological Clear Cells in High-Grade Intracranial Ependymal Tumors: A Retrospective Analysis from a Tertiary Care Hospital in Pakistan

Background:

Clear cell variant in ependymal tumors is rare. We aimed to compare the features and outcome of the World Health Organization (WHO) Grade 3 ependymal tumors with clear cells to the WHO Grade 3 classic anaplastic ependymoma (AE).

Materials and Methods:

A retrospective cohort study conducted at the Department of Neurosurgery, Aga Khan University, Pakistan, from 2003 to 2013. The medical records and radiology of patients with proven histopathology were reviewed. The analysis was done on SPSS 20.

Results:

Nine cases of clear cell variant and 23 cases of classic AE were found, both of which combined equated to 4% of the total tumor burden in 11 years. The median age of clear cell ependymoma (CCE) and AE were 49 and 37 years, respectively. Presenting symptoms included headache in 66% of CCE and 63% in AE, raised intracranial pressure accounting for 33% of CCE and 54% of AE, dizziness in 22% CCE and 39% AE, while seizures presented equally in both. Supratentorial location was observed in 77% CCE and 48% AE. Both showed hypointense signals on T1-weighted images of magnetic resonance imaging (MRI) while T2-weighted images showed hyperintensity in all cases of CCE but only 80% of AE. MRI characteristics such as the presence of cystic component were found in 89% of CCE and 68% of AE, necrosis in 33% CCE, and 22% AE, hemorrhagic in 22% CCE and 9% AE, and equivalent contrast enhancement. Gross total resection was achieved in 5 (55%) patients of CCE, compared to 6 (26%) patients in AE. Subtotal resection was done in 4 (44%) patients of CCE and 15 (65%) patients of AE. Radiotherapy was given to 5 (55%) patients of CCE and 12 (52%) patients of AE. Recurrence was observed in 77% cases of CCE and 70% of AE, with metastasis in 29% of AE and in only one patient of CCE. Repeat surgery was done in 3 (33%) cases of CCE and 8 (35%) cases of AE. Median progression-free survival and overall survival were 9 and 13 months, respectively, in CCE while 14 and 18 months, respectively, for AE.

Conclusion:

Clear cells in the WHO Grade 3 ependymal tumors are found mainly in a comparatively older adult population with a predilection for supratentorial location and are more aggressive in behavior with poorer outcome than AE.

Ependymal tumors with oligodendroglioma like clear cells: Experience from a tertiary care hospital in Pakistan

Background:

Ependymal tumors with oligodendroglioma like clear cells have never been reported from Pakistan. We aimed to see the features and outcomes of this rare entity.

Methods:

It was retrospective cohort conducted at the Department of Neurosurgery, Aga Khan University from 2003 to 2013. The medical records and radiology of patients with proven histopathology were reviewed. Analysis was done on SPSS 20.

Results:

Eleven cases of ependymal tumors with clear cells were found, which equated to 1.5% of the total tumor burden in 11 years. The median age was 49 years. Most common presenting symptom was headache 54.5%. Out of 11 patients, 9 patients had a supratentorial tumor. Magnetic resonance imaging showed hypointense signals on T1 and hyperintense signals on T2-weighted images in all cases. Contrast enhancement was found in 9 patients (77.8%), necrosis and hemorrhage was found in 4 (36%) and 3 (27%) patients, respectively. Immunohistochemistry showed glial fibrillary acidic protein and epithelial membrane antigen positivity in all cases. Ki-67 showed high proliferative index in 6 patients. According to the World Health Organization grading of ependymal tumors, 2 patients had Grade II tumors, and 9 patients had Grade III tumors with clear cells. Gross total resection was achieved in 6 (54.5%) and subtotal resection in 5 patients (45.4%). Recurrence was observed in 9 patients. Six patients died of the disease. Median progression-free survival and overall survival was 8 months and 10 months, respectively.

Conclusion:

Ependymal tumors with clear cells presented more commonly in Grade III lesions and were more aggressive in behavior with poorer outcome compared to similar studies.

Glycogen-rich pleomorphic xanthoastrocytoma with clear-cell features: confirmatory report of a rare variant with implications for differential diagnosis

Central nervous system space-occupying lesions with clear-cell features encompass a nosologically heterogeneous array, ranging from reactive histiocytic proliferations to neuroepithelial or meningothelial neoplasms of various grades and to metastases. In the face of such differential diagnostic breadth, recognizing cytoplasmic lucency as part of the morphological spectrum of some low grade gliomas will directly have an impact on patient care. We describe a prevailing clear-cell change in an epileptogenic left temporal pleomorphic xanthoastrocytoma surgically resected from a 36-year-old man. Mostly subarachnoid and focally calcified, the tumor was composed of fascicles of moderately atypical spindle cells with optically lucent cytoplasm that tended to intermingle with a desmoplastic mesh of reticulin fibers. Immunohistochemically, coexpression of S100 protein, vimentin, GFAP, and CD34 was noted. Conversely, neither punctate staining for EMA nor positivity for CD68 was seen. Mitotic activity was absent, and the MIB1 labeling index was 2-3% on average. Diastase-sensitive PAS-positive granula indicated clear-cell change to proceed from glycogen storage. Electron microscopy showed tumor cell cytoplasm to be largely obliterated by non-lysosomal-bound pools of glycogen, while hardly any fat vacuole was encountered. Neither ependymal-derived organelles nor annular lamellae suggesting oligodendroglial differentiation were detected. The latter differential diagnosis was further invalidated by lack of codeletion of chromosomal regions 1p36 and 19q13 on molecular genetic testing. By significantly interfering with pattern recognition as an implicit approach in histopathology, clear-cell change in pleomorphic xanthoastrocytoma is likely to suspend its status as a "classic", and to prompt more deductive differential diagnostic strategies to exclude look-alikes, especially clear-cell ependymoma and oligodendroglioma.

Differentiation of clear cell ependymoma of the cerebellum from hemangioblastoma by thallium-201 single photon emission computed tomography-case report-

A 57-year-old man suffered from dizziness for about one year and truncal ataxia for about one month. Magnetic resonance imaging demonstrated a cystic tumor with a homogeneously enhanced mural nodule located in the cerebellar vermis. Computed tomography angiography revealed a hypervascular nodule. These findings were compatible with hemangioblastoma. Thallium-201 single photon emission computed tomography ((201)Tl-SPECT) showed moderately high uptake in the early phase and moderately high retention in the delayed phase, whereas hemangioblastoma shows almost no retention in the delayed phase. The patient underwent total removal of the tumor. The histological diagnosis was clear cell ependymoma (CCE). CCE is a rare subtype of ependymoma, which resembles hemangioblastoma in histological and neuroimaging findings, but is considerably more aggressive. (201)Tl-SPECT can provide useful information for the preoperative differential diagnosis of infratentorial CCE and hemangioblastoma.