A 40-year-old male with an intraventricular tumor. Combined tanycytic ependymoma and subependymoma

Whorling Sclerosing Ependymoma of the Cervical Spinal Cord Presenting Tanycytic Histopathologic Features: A Rare Case Report

Tanycytic ependymoma is a neuroectodermal tumor that arises from ependymoglial cells or tanycytes. It is highly uncommon. We reported a 34-year-old man who was diagnosed with intradural-intramedullary tanycytic ependymoma, located at the level of C4-5 who had a 9-months history of neck pain and left arm pain, and numbness on fingers. One month prior to presentation, his left arm numbness and paresthesia deteriorated. The lesion was removed totally by C4, C5 hemilaminoplasty. The histologic pattern of this lesion was consisted of fascicles forming nebula-like whorling structures. Because of these structures, tanycytic ependymoma should be taken into consideration in the differential diagnosis of a whorling-sclerosing variant of meningiomas.

TERT promoter mutation and chromosome 6 loss define a high-risk subtype of ependymoma evolving from posterior fossa subependymoma

Subependymomas are benign tumors characteristically encountered in the posterior fossa of adults that show distinct epigenetic profiles assigned to the molecular group “subependymoma, posterior fossa” (PFSE) of the recently established DNA methylation-based classification of central nervous system tumors. In contrast, most posterior fossa ependymomas exhibit a more aggressive biological behavior and are allocated to the molecular subgroups PFA or PFB. A subset of ependymomas shows epigenetic similarities with subependymomas, but the precise biology of these tumors and their potential relationships remain unknown. We therefore set out to characterize epigenetic traits, mutational profiles, and clinical outcomes of 50 posterior fossa ependymal tumors of the PFSE group. On histo-morphology, these tumors comprised 12 ependymomas, 14 subependymomas and 24 tumors with mixed ependymoma–subependymoma morphology. Mixed ependymoma–subependymoma tumors varied in their extent of ependymoma differentiation (2–95%) but consistently exhibited global epigenetic profiles of the PFSE group. Selective methylome analysis of microdissected tumor components revealed CpG signatures in mixed tumors that coalesce with their pure counterparts. Loss of chr6 (20/50 cases), as well as TERT mutations (21/50 cases), were frequent events enriched in tumors with pure ependymoma morphology (p < 0.001) and confined to areas with ependymoma differentiation in mixed tumors. Clinically, pure ependymoma phenotype, chr6 loss, and TERT mutations were associated with shorter progression-free survival (each p < 0.001). In conclusion, our results suggest that subependymomas may acquire genetic and epigenetic changes throughout tumor evolution giving rise to subclones with ependymoma morphology (resulting in mixed tumors) that eventually overpopulate the subependymoma component (pure PFSE ependymomas).

Subependymoma and dysembryoplastic neuroepithelial collision tumor in the foramen of Monro: case report

Intracranial collision tumors have rarely been reported in the literature and generally include at least 1 malignant tumor component. Subependymoma with dysembryoplastic neuroepithelial tumor (DNET) is an as-yet unreported combination. Both components are uncommon tumors, and presentation in the foramen of Monro is even more unusual. A 16-year-old male patient with a past medical history significant for asthma presented with a 3-month history of headaches and radiographic evidence of mild obstructive hydrocephalus secondary to a nonenhancing ventricular lesion at the foramen of Monro. He underwent endoscopic biopsy and resection. Pathological analysis revealed distinct components of subependymoma and DNET. At the 1-year follow-up, the patient was doing well without regrowth of tumor. The authors describe a case of intracranial collision tumor demonstrating 2 grade I components: a novel combination of subependymoma and DNET.

Cerebellar ependymoma with overlapping features of clear-cell and tanycytic variants mimicking hemangioblastoma: a case report and literature review

BACKGROUND

Imaging and histology of clear-cell ependymoma and cerebellum-based hemangioblastoma are similar; distinguishing between them is a diagnostic challenge.

CASE PRESENTATION

A 62-year-old Chinese woman presented with an intermittent headache of 8 years' duration. Computed tomography and magnetic resonance imaging revealed a mass in the cerebellum. Neurological imaging suggested hemangioblastoma (HB). Histologically, the tumor included cellular and paucicellular areas, in which cells were arranged in nests or diffusely distributed; and a highly vascular area, in which tumor cells were arranged in clusters and separated by capillaries. At low magnification, the tumor mimicked cellular HB, but at high magnification, tumor cells showed clear cytoplasm instead of the vacuolated cytoplasm typically observed in HB. Moreover, spindly, bipolar elements resembling tanycytes were observed within the nest structures. Although these features indicated the possibility of ependymoma, neither true ependymal rosettes nor an ependymal-lined profile was observed. The tumor was characterized by prominent vascularity, but glomeruloid formation was absent. We saw pleomorphism in foci of some tumor giant cells, but pathologic mitosis and palisaded necrosis were absent. Most tumor cells were positive for glial fibrillary acidic protein and S100. Epithelial membrane antigen was expressed with a paranuclear dot-like or a ring-like pattern. The Ki-67 index was approximately 2%. Considering the patient's symptom, neurological imaging, and pathological findings, she was diagnosed as cerebellar ependymoma (WHO grade II).

CONCLUSIONS

Here, we report a case of ependymoma with overlapping clear-cell and tanycytic features, and review the literature to evaluate its real incidence. Pathologists should consider this rare diagnosis when confronted with a similar presentation.

Tanycytic ependymoma in a 76-year-old Puerto Rican male

Ependymoma is a slowly growing tumor in children and young adults originating from the wall of the ventricles or from the spinal canal that is composed of neoplastic ependymal cells. Tanycytic ependymoma is a rare variant of ependymoma usually arising in the intra medullary spine. The World Health Organization classifies the tanycytic ependymoma as a grade II tumor. The diagnosis of tanycytic ependymoma is challenging since the morphology of the lesions resemble those found in schwannoma and astrocytomas. In the present study, we show a case of a 76 years old male with a progressive paraparesis for 8 years, due to a spinal tumor. Radiological and histological studies were used to classify the tumor as tanycytic ependymoma. Therefore, it is important to be aware of tanycytic ependymoma and its immunohistochemistry profile in older patients, especially within the Caribbean Hispanic population. To our knowledge this is the oldest patient known to have this rare tumor and the first case reported in Puerto Rico.

Features of intraventricular tanycytic ependymoma: report of a case and review of literature

Tanycytic ependymoma is the rarest variant of ependymoma and occurs primarily in the spinal cord. Intracranial cases are even rarer. Only 9 ventricular and 5 subcortical tanycytic ependymoma have been reported in the literature. Amongst the 9 ventricular cases, only one tumor arose from the third ventricle. We report here another case of tanycytic ependymoma arising from the third ventricle completed with immunohistochemical, ultrastructural, and molecular pathology study. The patient was a 44 year-old male who presented with headache, nausea and visual disturbances of a few months duration. Neuroradiological findings showed a well-defined mass arising from the posterolateral wall of third ventricle. Histologically the tumor was composed of monotonous spindle cells arranged in fascicles without definitive perivascular rosettes. The tumor cells were diffusely positive for glial fibrillary acidic protein and epithelial membrane antigen, showed faint immunoreactivity for synaptophysin but were negative for neurofilament proteins and Ki-67 was less than 1%. Molecular studies showed absence of isocitrate dehydrogenase gene 1 and 2 mutation. A diagnosis of tanycytic ependymoma (TE) was made. From literature review with our current case included, intraventricular tanycytic ependymomas ranged from 1.8 to 4.0 cm. The age of patients ranged from 3.5 to 75 years with a mean age of 37.5 and a male predominance. The tumors occurred as well-defined, solitary ventricular mass without significant peritumoral edema with or without cystic changes. Histopathology and immunohistochemical profile are rather similar among different tumors. The immediate to short term outcome is excellent but long term follow up data is lacking.