Predictors of outcome in surgery for sporadic cerebellar hemangioblastomas

Hemangioblastomas are benign neoplasms, consisting of stromal cells surrounded by dense capillaries (3). Hemangioblastomas are most likely to be seen in adults, accounting for 2% of intracranial tumors and 7%–10% of posterior fossa tumors (9). Microsurgical resection is the treatment of choice for virtually all hemangioblastomas, and it is usually curative, but complete removal of large tumors with a rich vascular supply or deeply embedded in the brainstem may be challenging. External-beam radiation therapy may be useful in the management of these tumors. However, the tendency of hemangioblastomas to progress, recur, and generate new lesions suggests that this method of radiation may not be ideal because of the potential for cumulative neuronal damage. Several studies have suggested that radiosurgery is effective for solid hemangioblastomas, resulting in shrinkage or stabilization with low complication rates 4, 6, 8 and 11. Nevertheless, as Wanebo et al. (10) reported in their study, hemangioblastomas often had multiple periods of tumor growth alternated with periods of quiescence; this means that many untreated tumors sometimes remain the same size for several years. Because of the relatively short follow-up period after radiation reported in almost all of these studies, it is still difficult to determine whether the absence of tumor growth is attributable to a quiescent phase or to a positive response to the radiation therapy. However, when surgery is unsuitable, radiosurgery may be the preferred treatment for residual or recurrent and newly diagnosed solid hemangioblastomas with a diameter <3 cm and without mass effect.