"Anemone" cell (villiform) tumor of the brain.

At age 31, the patient developed hydrocephalus secondary to a brain lesion that had been present for 12 years. A ventriculoperitoneal shunt was performed, but a stereotactic biopsy did not establish a definitive diagnosis at that time. At age 34 the patient experienced spontaneous intratumoral and ventricular hemorrhage, which prompted radical surgical resection of the lesion. Histologic and immunocytochemical findings established a diagnosis of ependymoma; review of the ultrastructure of the tumor from the biopsy performed when the patient was 31 years old revealed the characteristics of an "anemone" cell neoplasm.