NEOPLASTIC TRANSFORMATION OF THE SUBEPENDYMAL CELL PLATE IN THE FLOOR OF THE FOURTH VENTRICLE (SUBEPENDYMAL SPONGIOBLASTOMA)

Abstract

The author describes a case of neoplastic transformation of the subependymal cell plate in the 4th ventricle. The growth was associated with an acquired hydrocephalus caused by the occlusion of the apertures of the 4th ventricles leading into the subarachnoid space. Three different components of the growth could be recognized: (1) a hyperplasia involving the ponticulus, (2) a diffuse neoplastic transformation of the subependymal cell plate in the floor of the 4th ventricle, and (3) a more massive neoplastic growth obliterating a portion of the caudal part of the 4th ventricle and involving its roof structures. Histologically, the neoplastic growth was designated as a subependymal spongioblastoma. Ependymitis may result in proliferations of somewhat similar appearance, but certain characteristic features of these inflammatory reactions distinguish them from a neoplastic process.