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

Abstract

BackgroundImaging and histology of clear-cell ependymoma and cerebellum-based hemangioblastoma are similar; distinguishing between them is a diagnostic challenge.Case presentationA 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).ConclusionsHere, 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.

Case of Clear Cell Ependymoma Successfully Treated with Preoperative Embolization

“…CCE express glial fibrillary acidic protein (GFAP) and its intensity is stronger and more extensive than in HB. 12) In addition, our group had reported that 201 Tl-SPECT can help to differentiate between cerebellar CCE and HB to establish the correct preoperative diagnosis, however, not performed in this case unfortunately. 10) …”

A Solitary Hemangioblastoma in the Lateral Ventricle: Case Report and Review of the Literature

“…So, according to the imaging ndings of this patient, the ependyma, central neurocytoma and choroidal papilloma were mainly considered in the differential diagnosis of tumors in the lateral ventricle. [20][21][22] To diagnose the intracranial hemangioblastoma, MRI is superior to CT. 23 On MRI, there are several types of hemangioblastoma 2,24−25 : (1) Large unenhanced cyst with enhanced small nodule; (2) Simple cyst without enhancement; (3) Simple cyst with enhanced wall; (4) The cyst with enhanced wall is accompanied by enhanced small nodule. In this case, the tumor was consistent with the last type.…”

Synchronous Occurrence of Hepatocellular Carcinoma and Renal Cell Carcinoma: A Case Report

“…There were six cases with the synchronous occurrence of HCC and RCC reported in the literature (Table 1) [11][12][13][14][15][16] . The median age was 55 years (42-72).…”