Background Cavernous malformations are relatively rare vascular anomalies which typically follow a benign clinical course. The vast majority of these lesions are small and only become clinically significant when they induce seizures or hemorrhage. Rarely, cavernous malformations may grow to large sizes without a clinically significant acute hemorrhage, thus resulting in a presentation consistent with a large intracranial mass lesion. These giant cavernous malformations present a diagnostic challenge, as CT and MRI are frequently unable to distinguish them from neoplastic pathology.