Hemangioblastoma

Hemangioblastomas are usually located in the posterior fossa (the space at the base of the skull which holds the cerebellum and brain stem) in the adult. On microscopic examination of hemangioblastoma the cells are found to be benign and not malignant. There are three different cell types which have led to classification of three types of hemangioblastoma, but this classification does not seem to have any impact on the treatment or eventual outcome for this tumor. It can occur randomly for no known reason but occurs more frequently as part of a congenital syndrome called von Hippel-Lindau. Von Hippel-Lindau is associated with multiple abnormalities of different organ systems and with an excess of red blood cells (erythrocytosis). Hemangioblastomas are 1-2.5% of intracranial tumors. They are rare supertentorially tending to occur much more frequently in the cerebellum. 1.5-2.5% of spinal cord tumors are hemangioblastomas. Therefore of all hemangioblastomas, 85% occur in the cerebellum, 3% are in the spinal cord, 2-3% occur in the medulla, 20% occur as part of the von Hippel-Lindau syndrome mentioned earlier. Von Hippel-Lindau present earlier in the third decade (the patients 20's), sporadic cases present when patients are in their 30's.

The presentation is of a cerebellar mass which can cause increased intracranial pressure with nausea, vomiting, headache or findings of cerebellar dysfunction such as loss of coordination and imbalance. In addition, retinal detachment can be seen if a hemangioblastoma in the retina hemorrhages. Erythrocytosis, mentioned above, can cause difficulties with circulation of blood and sometimes stroke.

The diagnosis of hemangioblastoma is made by MRI scan. Laboratory tests should be done to determine the red-blood cell count to rule out polysidemia. In addition, catecholemines should be assessed because a tumor of the adrenal gland (i.e. pheochromocytoma) can occur with von Hippel-Lindau.

Surgical treatment of hemangioblastoma requires removal of the frequently associated Mural nodule. The lesion is usually cystic and its cystic wall does not need to be removed as long as the nodule has been completely resected. The problems in surgery include risk to the cardio-respiratory system because these tumors frequently are adherent to the floor of the fourth ventricle which is close to the cardio-respiratory control center. X-ray therapy is indicated only for small deep lesions which are inoperable. Otherwise surgery is the treatment of choice. X-ray therapy does not prevent recurrence and therefore its indications for this tumor are extremely limited.