Liponeurocytoma of the left lateral ventricle--case report and review of the literature.

The reported liponeurocytoma of the left lateral ventricle in a 35-year-old man represents the fifth recorded case of a supratentorial intraventricular liponeurocytoma. In this location, liponeurocytomas are very exceptional, whereas it is the typical site for classic central neurocytomas. Conversely, neurocytomas of the cerebellum are predominantly liponeurocytomas with until now more than 25 reported cases. Thus, cerebellar liponeurocytoma is the most frequent neuroepithelial CNS tumor with adipose-like cells followed by ependymomas with a lipid component and supratentorial intraventricular liponeurocytoma. Adipose-like cells in neurocytomas may originate by lipidization of tumor cells, metaplastic transformation of neuroectodermal cells into fat cells or by true adipocytic differentiation. The present case showed also focal glial differentiation with GFAP-positivity of some tumor cells as often seen in cerebellar liponeurocytomas but much rarer in central neurocytomas. Pathogenetic and nosologic implications of supratentorial intraventricular liponeurocytomas are discussed. Future WHO tumor classification should consider that liponeurocytomas are not restricted to the cerebellum. Reports on cerebellar liponeurocytomas with a less favorable clinical course suggest a WHO grade II for liponeurocytomas.