Preoperatively Confirmed Idiopathic Myointimal Hyperplasia of the Mesenteric Veins: A Case Report

Abstract

Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a rare cause of colonic ischemia. First documented in the literature in 1991, this condition has remained exceedingly rare, with only a limited number of case reports since its initial mention. It involves proliferation of intimal smooth muscle within the mesenteric veins, resulting in colonic ischemia due to venous constriction and non-thrombotic occlusion. Patients experience a prolonged clinical course and adverse outcomes due to its rarity and nonspecific symptoms. The definitive diagnosis is typically confirmed after surgical resection of the affected colon, as initial biopsies are not deep enough to confirm the diagnosis. Histological examination of these biopsies reveals arteriolization of capillaries, subendothelial hyaline deposits, and fibrin thrombi. We present a case of a patient with a one-year history of diarrhea and abdominal pain. Biopsy samples obtained during colonoscopy showed colitis and proliferation of muscularized capillaries, consistent with IMHMV, prior to colon resection. The patient ultimately underwent laparoscopic total abdominal colectomy to the distal one-third of the rectum with end ileostomy. IMHMV is commonly treated surgically and mismanagement of this condition involving corticosteroids and immunomodulatory agents may result in unfavorable outcomes. This case report is one of the few cases of IMHMV diagnosed preoperatively within existing literature, which highlights a rare etiology of nonspecific colitis, emphasizing the critical divergence in its management approach.