Hemangioblastomas with blood supply from the dural arteries--two case reports.

Hemangioblastomas are benign vascular tumors that often occur in the cerebellum, and are located near the pia mater. The blood supply is usually received through the pia mater, and rarely through the external carotid artery. The present cases of hemangioblastoma received blood supply from the external carotid artery (occipital artery) and a branch of the internal carotid artery (carotico-tympanic artery or artery of Bernasconi Cassinari) through the dural branches. The dural arteries were not the main feeders in either case, but preoperative embolization of the occipital artery contributed to minimum bleeding during the operation in one case. Incomplete resection of hemangioblastoma is related to multicentricity of the tumors, small mural nodules, or brain stem involvement. Angiography is valuable for demonstrating arterial supply to small or multiple mural nodules. Conventional angiography is necessary for investigation of the external carotid artery branches.