hemangioblastoma

Hemangioblastoma is a WHO Grade I benign tumor composed of stromal cells and abundant capillary networks, making it highly vascular. It accounts for 1-2% of all intracranial tumors but represents 7-12% of posterior fossa tumors. The tumor has a strong association with von Hippel-Lindau (VHL) disease - approximately 25% of hemangioblastomas occur in VHL patients, while 60-80% of VHL patients develop hemangioblastomas. The VHL gene (chromosome 3p25-26) functions as a tumor suppressor. Sporadic cases typically present as single lesions in the fourth decade, while VHL-associated cases are often multiple and present earlier. The tumor's stromal cells can secrete erythropoietin, leading to secondary polycythemia in 5-25% of cases. Clinical presentation depends on location but commonly includes headache, nausea, vomiting, and cerebellar signs (ataxia, dysmetria, nystagmus). On imaging, hemangioblastomas appear as well-circumscribed cystic lesions with intensely enhancing mural nodules. Complete surgical resection is curative, with excellent prognosis for benign lesions.