[Subependymal giant cell astrocytoma].

Subependymal giant-cell astrocytomas (SEGA) are rare brain tumors. They occur typically in the walls of the lateral ventricles and very seldom in the wall of the third ventricle. In our experience, all patients with SEGA have had tuberous sclerosis. Between January 1950 and May 1990, of our 345 patients with tuberous sclerosis 22 were found to have SEGA. The diagnosis being made histologically in symptomatic cases or by clinical or neuroradiologic methods. The histological, immunohistochemical and ultrastructural features of this unique tumor are discussed. To date, histopathologic methods have not resolved the issue of whether these tumors are exclusively astrocytic or neuronal in nature, or show features of both. Modern immunohistochemical and/or molecular-biological techniques will no doubt elucidate the histogenesis of this highly characteristic, albeit polymorphous tumor.