1) A benign tumour of the nervous system that may occur sporadically or in association with Hippel-Lindau disease. It accounts for approximately 2% of intracranial tumors, arising most frequently in the cerebellar hemispheres and vermis. Histologically, the tumours are composed of multiple capillary and sinusoidal channels lined with endothelial cells and clusters of lipid-laden pseudoxanthoma cells. Usually solitary, these tumours can be multiple and may also occur in the brain stem, spinal cord, retina, and supratentorial compartment. Cerebellar hemangioblastomas usually present in the third decade with intracranial hypertension, and ataxia. (From DeVita et al., Cancer: Principles and practise of Oncology, 5th ed, pp2071-2)

2) A hemangioma especially of the cerebellum that tends to be associated with von Hippel-Lindau disease.