Cerebellar clear cell ependymoma mimicking hemangioblastoma: Its clinical and pathological features

Abstract

BACKGROUND As the clinical and pathological significance of cerebellar clear cell ependymoma (CCE) has not been recognized in the past, eight cases of cerebellar CCEs were studied. METHODS Subjects were six men and two women, and their ages ranged from 23 to 64 years old. Their neuroradiological, operative, and pathological features were reviewed. RESULTS The tumors frequently showed high vascularity on angiography and marked enhancement on computerized tomography. Grossly, six tumors exhibited a “cyst with mural nodule” and two were mostly solid containing small cysts. At operation, the tumor nodules were dark red in color and the cysts contained xanthochromic fluid. Microscopically, all tumors displayed mostly clear round cells and abundant blood vessels. Although they commonly lacked the characteristic features of ependymomas, immunostaining and electron microscopy confirmed their ependymal origin. CONCLUSIONS The results indicate that cerebellar CCEs closely mimic hemangioblastoma both clinically and pathologically, which suggests CCE should be considered in the differential diagnosis of vascular tumors of the cerebellum. Some diagnostic clues to differentiate CCE from hemangioblastoma are discussed.