Spontaneous hemorrhage in an intraorbital arteriovenous malformation.

OBJECTIVE To report the clinical findings and management of spontaneous hemorrhage in an unsuspected intraorbital arteriovenous malformation. DESIGN Interventional case report. METHODS Review of clinical findings, radiologic studies, and treatment of the patient. RESULTS A 75-year-old woman sought treatment for the rapid onset of severe proptosis. Orbital exploration of a "mass" imaged on computed tomography scan and magnetic resonance imaging resulted in massive intraoperative hemorrhage. Subsequent arteriographic and histopathologic analysis confirmed an underlying orbital arteriovenous malformation. CONCLUSIONS Spontaneous intraorbital hemorrhage from an arteriovenous malformation is extremely rare, but should be considered in the differential diagnosis of rapidly progressive proptosis.