title: Clear cell ependymoma. A histological variant with diagnostic implications.
abstract: Four cystic brain tumours, one from the frontal lobe, one in the third ventricle and two in the cerebellum, were studied histologically including immunostaining and electron microscopy. Anatomically, all the tumours were located within or adjacent to the ventricular system. By light microscopy, the tumours had a largely honeycomb pattern and were made up of clear cells. Some of the clear cells showed positive for GFAP. Leu 7, Factor VIII and NSE were negative. Electron microscopy of the areas with clear cells revealed densely packed polyhedral cells with clear cytoplasm. They had well developed intercellular junctions, microvilli and some cilia which confirmed their ependymal derivation. Perivascular pseudorosettes or papillary features were only seen in limited areas, where GFAP was strongly positive in the tumour cell processes. As these tumours mimic oligodendroglioma and cerebellar haemangioblastoma, they are called as "clear cell ependymoma" to obviate such errors in diagnosis.
authors: Department of Neurosurgery, Kitasato University School of Medicine, Kanagawa, Japan.
authors: N
authors: N
authors: Kawano
authors: K
authors: K
authors: Yada
authors: S
authors: S
authors: Yagishita
mesh_terms: D000328:Adult; D000943:Antigens, Differentiation; D001932:Brain Neoplasms / Q000145:classification / Q000175:diagnosis / Q000473:pathology* / Q000648:ultrastructure; D018959:CD57 Antigens; D002528:Cerebellar Neoplasms / Q000145:classification / Q000175:diagnosis / Q000473:pathology / Q000648:ultrastructure; D002675:Child, Preschool; D004806:Ependymoma / Q000145:classification / Q000175:diagnosis / Q000473:pathology* / Q000648:ultrastructure; D005169:Factor VIII / Q000032:analysis; D005260:Female; D014644:Genetic Variation; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D010751:Phosphopyruvate Hydratase / Q000032:analysis
chemical_list: D000943:Antigens, Differentiation; D018959:CD57 Antigens; D005904:Glial Fibrillary Acidic Protein; D005169:Factor VIII; D010751:Phosphopyruvate Hydratase