The evolution of the anaplastic cerebellar liponeurocytoma: case report and review of the literature.

Cerebellar liponeurocytoma, first recognized as a distinct entity in the revised WHO classification of Tumors of the Central Nervous System in 2000, is a rare tumor with characteristic histological features and predominant location in the cerebellum. The proliferative index is usually low, and previous reports supported a favorable prognosis. We report a case of a second recurrence of a cerebellar liponeurocytoma with increased proliferative and mitotic activity in which extensive immunohistochemical characterization and genetic profiling were performed. The tumor specimen was characterized in terms of genetic changes frequently associated with gliomas and medulloblastomas. Considering the low number of reported cases, the prognosis of cerebellar liponeurocytoma seems difficult to assess. Our case suggests the existence of different histological grades of cerebellar liponeurocytoma and its possible progression towards a dedifferentiated, malignant phenotype, which has not yet been adequately taken into consideration in the current WHO classification.