Cerebellum, Hemangioblastoma

Hemangioblastomas are benign, slowly growing tumors, classified as WHO grade I, and are typically present in the cerebellum. They are composed of a proliferation of variable sized thin walled blood vessels and large neoplastic cells with pink to clear cytoplasm and fine vacuoles containing lipid, which stain positive with PAS. Mast cells can be seen.

On immunohistochemistry, the tumor cells are positive for CD34 and NSE and negative for EMA and keratin. Hemangioblastoma can be sporadic or part of Von Hippel-Lindau disease.