A MRI showing hemangioblastomas in the brain and spine of a VHLS patient, courtesy Public Library of Science, via Wikipedia
Von Hippel-Lindau Syndrome is a rare genetic disease which, like tuberous sclerosis, causes numerous small tumors (hemangioblastoma) to grow throughout the body. Although the tumors are often benign, they tend to congregate in the eyes, on blood vessels, and on glands. This causes blindness, high blood pressure, metabolic symptoms (such as sudden rage or muscle weakness).
The only treatment is surgical removal of the tumors before they become dangerously large. Patients require lifetime monitoring to ensure that no new tumors grow. The prognosis for patients is usually poor if the tumors become large, widespread, or are located in areas which are inaccessible to surgery.