Large retroperitoneal hemangioma encompassing the renal vein.

Retroperitoneal hemangioma (RH) is a rare and benign vascular malformation. RH may be detected incidentally or present with symptoms due to local invasion of adjacent structures. Management options include surgical resection, as well as serial observation with routine imaging. We describe a retroperitoneal hemangioma encompassing the renal vein that was discovered during diagnosis of acute appendicitis, and characterize diagnostic magnetic resonance imaging (MRI) findings seen with this condition.