Central liponeurocytoma.

The 2000 World Health Organization has included cerebellar liponeurocytoma in the category of glioneuronal tumors of the central nervous system. Once termed medullocytoma and considered an embryonal tumor, a variant of medulloblastoma, its indolent behavior and morphologic features prompted this nosologic change. Biphasic in appearance, the tumor consists of well-differentiated neurons with the cytology of neurocytes in addition to a population of lipidized cells resembling mature adipose tissue. Such tumors occur in older adults and have a relatively good prognosis. Linking the concept of liponeurocytoma to its occurrence in the cerebellum unnecessarily obscures the existence of similar neoplasms at other sites, such as among classic central neurocytomas of the lateral and third ventricles. Indeed, two such cases have briefly been reported. To these, we add a third example, the first to be ultrastructurally examined. Our case provides evidence that the lipid vacuoles progressively accumulate and coalesce within cells retaining neurocytic features. Thus, these distinctive lesions are the result of tumoral lipidization, rather than true adipose metaplasia.