A spinal tumor showing mixed features of ependymoma and hemangioblastoma: a case report and literature review.

We report an intramedullary spinal tumor consisting of an ependymoma and a hemangioblastoma (HB). A 37-year-old woman presented with progressive bilateral lower limb sensory and motor deficits. Magnetic resonance imaging showed a single intramedullary mass in the thoracic cord (T4-T6 level). Clinically, the patient had no von Hippel-Lindau disease and neurofibromatosis type 2. Metastatic carcinomas including renal cell carcinoma were altogether negative. Complete surgical resection was performed. Histologically, the tumor consisted of a mixed ependymoma and HB. Tumor cells of ependymoma displayed a rather uniform appearance with round to oval nuclei having salt-and-pepper-like chromatin, forming perivascular pseudorosette structures with radially arranged, tapering cell processes extending to intratumoral blood vessels. Stromal cells of HB had vacuolated or homogeneously eosinophilic cytoplasm and variable sized hyperchromatic nuclei within a background of capillaries. Immunohistochemically, tumor cells of ependymoma were strongly positive for glial fibrillary acidic protein (GFAP), focally positive for epithelial membrane antigen (EMA) and D2-40 in a dot-like or ring-like pattern. Stromal cells of HB showed immunoreactivity for S100, vimentin, inhibin-α, D2-40, EMA and cytokeratins (CK: AE1/AE3, CK19). A review of the literature, in conjunction with the present case, shows that ependymomas and HBs may have a close relationship with each other.