The Art of Mimicry: Anterior Clinoid Dural-Based Cavernous Hemangioma Mistaken for a Meningioma.

Background: Cavernous hemangiomas account for 5%-13% of central nervous system vascular lesions. They are usually found intra-axially but rarely involve extra-axial structures, most commonly the middle cranial fossa. A cavernous hemangioma manifesting as a clinoid meningioma is extremely rare.

Case Description: A 36-year-old man presented with an asymptomatic intracranial mass found incidentally after a motor vehicle accident. Preoperative magnetic resonance imaging revealed a well-defined dural-based lesion arising from the right anterior clinoid process that was nearly homogeneously enhancing. The radiologic diagnosis was meningioma. The mass was resected via a right pterional craniotomy with microsurgical technique. Complete resection of the mass was performed with no complications and no significant bleeding. Contrasting with the radiologic and gross tumor appearance, histopathologic examination revealed dilated vascular spaces, sclerotic vessels without intervening neural tissue, and intravascular thrombi suggesting slow blood flow-all consistent with cavernous hemangioma.

Conclusions: Anterior clinoid dural-based cavernous hemangiomas are extremely rare. Although preoperative diagnosis is difficult using imaging, this etiology should be considered for any dural-based middle fossa lesion, owing to the tendency for these lesions to bleed heavily during resection in some instances.