Cerebellar liponeurocytoma with unusually histopathology: a case report

Cerebellar liponeurocytoma (LPN) is a rare central nervous system tumor. We encountered a 45-year-old woman with cerebellar LPN who had a three months history of headaches and mild ataxia. MRI revealed a mixed signal tumor in the cerebellar vermis. The tumor was totally removed. Histologically, a highly cellular neoplasm composed of monomorphic small round neuronal cells mixed with lipomatous cells. There was "Starry sky appearance" structure in the tumor. At high magnification, there were two different type histopathological morphologies. One was more than one large cell in one lacuna with clear cytoplasm. Another was huge cell with mononuclear or polynuclear and abundant mucinous cytoplasm. There were neuropil-like islands. Immunohistochemistally, neuronal cells were diffuse positive for Syn and NeuN. The lipomatous cells were positive for Syn, NeuN and GFAP. The "Starry sky appearance" cells were positive for GFAP and S100 and negative for Syn and NeuN. The proliferation index was about 2%. The pathological diagnosis was cerebellar LPN. The patient underwent radiation therapy after operation and no recurrence follow-up of 32 months. We do not know the "Starry sky appearance" cells were what really. Moreover, we listed the different diagnosis of cerebellar LPN in pathology.