Lipomatous differentiation in a medulloblastoma.

A surgically resected medulloblastoma of the left cerebellum in a 42-year-old man contained numerous mature fat cells; many of these adipocytes expressed glial fibrillary acidic protein (GFAP), S-100 protein, and vimentin as seen by immunocytochemistry. The cellular parts of the tumor showed varying immunoreactivities for GFAP, S-100 protein, neuron-specific enolase, and synaptophysin. It is concluded that this tumor exhibits a unique spectrum of differentiation along multiple lines, including transformation of neuroectodermal cells to fat cells. The significance of this new type of differentiation in primitive neural tumors remains to be elucidated.