Idiopathic Myointimal Hyperplasia of the Mesenteric Veins: A Rare Imitator of Inflammatory Bowel Disease.

Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a rare cause of chronic colonic ischemia characterized by intimal smooth muscle proliferation and luminal narrowing of the small to medium sized mesenteric veins. It predominantly affects the rectosigmoid colon in otherwise healthy, middle-aged males. Definitive diagnosis and treatment are surgical; however, patients are frequently misdiagnosed, which often results in a protracted clinical course. We describe a case of IMHMV presenting as left hemicolitis in a 53-year-old male, as well as the endoscopic, histopathologic, and radiographic findings that established the diagnosis.