Case Report Idiopathic Myointimal Hyperplasia of Mesenteric Veins of the Ileum and Colon in a Patient with Crohn’s Disease: A Case Report and Brief Review of the Literature Sharon J. Song and Stuti G. Shroff Department of Pathology and Laboratory Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA Correspondence should be addressed to Stuti G. Shrof; stuti.shrof@uphs.upenn.edu Received 21 May 2017; Accepted 12 July 2017; Published 15 August 2017 Academic Editor: Hiroko Kuwabara Copyright © 2017 Sharon J. Song and Stuti G. Shrof. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a rare disease characterized by intimal smooth muscle proliferation, leading to the thickening of small to medium-sized mesenteric veins. Tis vascular disease mimics infammatory bowel disease (IBD) clinically and endoscopically, while showing ischemic mucosal changes without the classic features of IBD on biopsy. Given the mixed picture, this entity is frequently misdiagnosed. Surgical resection of the diseased bowel segment reveals the true etiology of the pathology and is curative. We describe a case of a 59-year-old man with a long-standing history of Crohn’s disease refractory to medical therapy and status afer multiple small bowel resections. Te patient underwent a subtotal abdominal colectomy with pathology showing dense, indurated mesenteric adipose tissue, signifcant muscularis propria hypertrophy, and myointimal hyperplasia of the mesenteric veins in a peri-ileal and pericolic distribution, as confrmed by elastin stain. No evidence of mucosal ischemic changes or fndings of chronicity or acuity were seen. IMHMV, a rare disease with a mixed presentation, poses a signifcant diagnostic challenge to clinicians and pathologists. 1. Introduction Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a poorly understood disease that poses a diagnostic challenge to clinicians and pathologists. Clinically and endoscopically, patients appear to have infammatory bowel disease (IBD); however, biopsies show ischemic abnor- malities without the classic features of IBD. Patients have a relatively protracted clinical course refractory to medical treatment, and it is not until the diseased bowel segment is resected that histology reveals the underlying etiology. IMHMV is characterized by thickened small and medium- sized mesenteric veins with the hallmark feature of intimal smooth muscle proliferation, leading to luminal occlusion and mucosal ischemic changes. Herein, we present a case of IMHMV in a 59-year-old man with a long-standing history of Crohn’s disease. 2. Case Presentation A 59-year-old man with a 30-year history of Crohn’s disease was referred to our institution for ongoing symptoms of bloating, abdominal pain, and alternating bouts of consti- pation and diarrhea with occasional incontinence despite treatment with infiximab and azathioprine. He had three prior small bowel resections at the ileocecal junction for intestinal obstruction with the last surgery performed 15 years ago. Te two prior resections, according to pathology reports available for review, demonstrated changes consistent with Crohn’s disease, including transmural infammation and multiple infammatory pseudopolyps. His most recent colonoscopy at the outside institution showed patchy mild infammation from the rectum to descending colon; however, surveillance was limited by adhe- sions and strictures preventing passage of the colonoscope Hindawi Case Reports in Pathology Volume 2017, Article ID 6793031, 6 pages https://doi.org/10.1155/2017/6793031