|This article has been reviewed by the NeuroWiki Editorial Board|
Axial T2 MRI of cerebellar hemangioblastoma
|Cell of origin||meningeal cell of unknown origin|
Hemangioblastomas are WHO grade I tumors of unknown cellular origin. They present most commonly in the posterior fossa but can occur anywhere in the nervous system. While they can occur sporadically, they are also associated with von Hippel-Lindau (VHL) disease.
Hemangioblastomas account for 2% of all intracranial tumors, and 10% of posterior fossa tumors. They also represent 2%-3% of intramedullary spinal cord tumors. Approximately 25% of hemangioblastomas are associated with VHL disease. Men are more commonly affected than women (ratio M:F ranges from 1.3:1 to 2:1).
Most patients with sporadic tumors are diagnosed in their 5th decade of life. VHL patients are usually diagnosed in their 3rd decade of life due to the multiplicity of the disease. Posterior fossa hemangioblastomas can result in obstructive hydrocephalus along with headaches and signs/symptoms of cerebellar dysfunction. Tumors in the spinal cord can cause spinal pain, spasticity, weakness, and other upper motor neuron symptoms/signs.
Angiographic pattern is a large avascular posterior fossa mass with a small highly vascular mural nodule; CT shows a large, low density, cystic appearing cerebellar mass; following contrast enhancement a mural nodule that enhances strongly and relatively uniformly can be identified in 75% of cases; MRI shows cystic component that is hypointense compared to brain on T1 and hyperintense on T2, enhancement of the nodule following contrast is intense. Not all tumors need to have a cystic component. Flow-voids can often be seen on T2 weighted imaging. Brainstem and intramedullary tumors tend to be more solid than cystic.
Histologically one sees numerous capillary channels that form a plexus. Between the capillary channels are interstitial cells with foamy, clear cytoplasm. Three cell types are present microscopically, endothelial cells lining capillarly spaces, pericytes adjacent to the endothelial cells, and large round or polygonal stromal cells (clear cells).
von Hippel Lindau’s (VHL) disease
- VHL gene localized to chromosome 3p
- inheritance is autosomal dominant
- most typically are adult tumors that present in the third to fifth decades
- other associations with VHL: retinal angiomatosis (hemangiomas) (60%) (multiple hemangioblastomas are seen only in VHL), hepatosplenomegaly, renal cell carcinoma (25% of patients), pheochromocytoma (10% of patients), elevated hematocrit (20% of patients) due to secretion of erythropoietin by the hemangioblastoma, pancreatic cysts; there are no cutaneous findings
- typically present with cerebellar hemangioblastoma in 60% of cases, 40% present with retinal angioma, and 25% present with renal cell carcinoma
- screening test: VMA and metanephrines; if > 10 years of age, retinal examination
- pheochromocytomas are tumors of the adrenal medulla
- erythrocytosis is more common in solid hamangioblastomas; erythrocytosis subsides after hemangioblastoma removal in 50% of patients
- Remember: Blood, brain, eyes, kidneys, pancreas, liver, spleen
Primary treatment is surgical resection. Stereotactic biopsy is generally not performed due to the intense vascularity of these tumors. Circumferential dissection without violation of the tumor is the preferred method of resection. Piecemeal resection often results in significant hemorrhage. Preoperative embolization as an adjunct to surgery has been advocated but is not always necessary. Radiation therapy or radiosurgery are alternative choices that have been shown to result in improved local control rates. There are no well-studied chemotherapy regimens for hemangioblastoma. Despite complete surgical resection, recurrence may occur in up to 25% of cases.