Differentiated cerebral neuroblastoma: a tumor in need of discovery.

A tumor with the clinical and light microscopic appearance of an oligodendroglioma that occurred in the lateral ventricles of a 25-year-old man is described. On further study this tumor proved to have the ultrastructural features typical of neuroendocrine tumors, and the presence of neuron-specific enolase was demonstrated by immunoperoxidase staining. This unusual presentation of a neuroendocrine tumor, which was entirely amitotic and free of atypia, raises important questions concerning both the true incidence of such cerebral differentiated neuroblastomas and their biologic behavior. The importance of electron microscopy and immunostaining techniques, which should be used more frequently to uncover additional cases of this tumor, is stressed.