A Rare Suprasellar Ependymoma With Negative Targeted Fusion Testing: Diagnostic Value of Histopathological, Immunohistochemical, and Ultrastructural Findings

Ependymomas arising in the supratentorial region preferentially appear in the third ventricle or cerebral parenchyma, making a suprasellar location extremely rare.We report a case of a 36-year-old woman who presented with incomplete bitemporal hemianopsia and was found to have a suprasellar mass lesion on magnetic resonance imaging.The patient underwent endoscopic transsphenoidal surgery with gross total resection.Pathological analysis of the resected tumor demonstrated perivascular pseudorosettes and immunohistochemical positivity for glial fibrillary acidic protein, vimentin, cytokeratin CAM5.2, and epithelial membrane antigen.Ultrastructural findings revealed intercellular junctional complexes, microvilli, and intermediate filaments on electron microscopy.Molecular analysis using reverse transcription-polymerase chain reaction failed to detect a gene fusion.According to the WHO classification 2021, the tumor was diagnosed as supratentorial ependymoma NEC (not elsewhere classified).To our knowledge, only a small number of cases of ependymoma developing in the suprasellar region have been reported in the literature.Radial glia-like cells present in the adult central nervous system, specifically in the subventricular zone, may serve as the origin for adult supratentorial ependymomas.This case highlights that suprasellar ependymoma, though rare, should be considered in the differential diagnosis of sellar-suprasellar tumors.Molecular testing for defining gene fusions is important for precise classification of future cases.