Cavernous sinus hemangiomas: a series, a review, and an hypothesis.

Cavernous sinus hemangiomas represent 3% of all benign cavernous sinus tumors. They are dangerous tumors because of the risk of excessive bleeding, but they are easier to dissect from surrounding structures than meningiomas because of the presence of a pseudocapsule. Three cases where total excision was achieved with minimal blood loss, without stroke, and with preservation of cranial nerve function in 2 cases are reported, and 50 cases from the literature are reviewed. Hemangiomas can be distinguished preoperatively from over one-half of meningiomas by their marked hyperintensity on T2-weighted magnetic resonance imaging. They arise within the cavernous sinus and extend laterally by dissecting between the two layers of dura lining the floor of the middle fossa. Cranial nerves III, IV, and V remained stretched over the tumor surface within the overlying dura, whereas cranial nerve VI is found within the tumor and is the most difficult cranial nerve to preserve. Principles for successful and safe excision include preoperative assessment of the safety of temporary or permanent carotid artery occlusion, obtaining early proximal carotid artery control, carefully developing the plane between the dura and the tumor pseudocapsule, early devascularization of the tumor, and avoiding "piecemeal" tumor resection. A few cases demonstrated tumor shrinkage with radiation therapy which should be considered for patients with incomplete tumor excision or who are too ill to undergo surgery.