Yale University School of Medicine New Haven, CT, United States
Raquel N. Rozner, MD1, Andrea Barbieri, MD1, Marie Robert, MD1, Vikram Reddy, MD, PhD1, Deborah D. Proctor, MD1, Darrick Li, MD, PhD2 1Yale University School of Medicine, New Haven, CT; 2Yale School of Medicine, New Haven, CT
Introduction: Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a rare cause of intestinal ischemia that is poorly understood. It mimics inflammatory bowel disease and nonocclusive ischemic colitis, but does not respond to medical therapy. Here we present a case of abdominal pain and severe left-sided colitis without response to antibiotics or immunosuppression.
Case Description/Methods: A 52-year-old male with type 2 diabetes and hypertension presented with six months of unexplained abdominal pain and hematochezia. Two months prior to presentation, CT of the abdomen and pelvis revealed severe thickening from the descending colon to the rectum with patent vasculature. One month later, a colonoscopy revealed congested mucosa in the descending and sigmoid colon, and rectum. Pathology was consistent with acute ischemic injury and possible small vessel vasculitis. Two weeks later, he presented to an outside hospital with worsening symptoms and was treated with antibiotics and pulse dose steroids without improvement. He was transferred to our hospital for further evaluation.
The patient’s abdomen was diffusely tender and distended. Laboratory workup showed leukocytosis with negative infectious workup. Colonoscopy revealed a continuous area of pale, ulcerated, strictured and necrotic mucosa from the mid rectum to the sigmoid colon. Biopsies showed an ischemic type of mucosal injury with numerous fibrin thrombi within mildly dilated lamina propria vessels, suggestive of IMHMV. He underwent low anterior resection with end colostomy. Surgical pathology from the resected specimens revealed IMHMV with mucosal and submucosal necrosis (Figure). Since then, his abdominal pain has almost fully resolved.
Discussion: The incidence of IMHMV is unknown and is likely under-recognized. It is a frequently segmental colitis with a predilection for the left colon. Histologically, it is characterized by intimal smooth muscle thickening in the small and medium sized mesenteric veins with arterial sparing as well as “arterialized” capillaries interspersed between colonic crypts in the mucosa. Its pathophysiology is speculated to be secondary to venous remodeling from venous hypertension related to abnormal arteriovenous communications in the sigmoid mesentery. Most patients have resolution of symptoms after the affected bowel segment is resected. IMHMV should be considered in patients with unexplained segmental colitis that is unresponsive to medical therapy, as surgical resection is often curative.
Figure: (A) Hematoxylin and eosin stain of colonic wall demonstrates nearly occluded mesenteric vein within the subserosa (vein on left, accompanying artery on right), 200x magnification. (B) Smooth muscle actin immunohistochemical stain (brown chromagen) reveals marked abnormal smooth muscle deposition within the vein, in excess of that present in the accompanying artery (200x magnification).
Raquel Rozner indicated no relevant financial relationships.
Andrea Barbieri indicated no relevant financial relationships.
Marie Robert indicated no relevant financial relationships.
Vikram Reddy indicated no relevant financial relationships.
Deborah Proctor: AbbVie – Consultant, Primary Investigator for Multi-Center Trial.
Darrick Li indicated no relevant financial relationships.
Raquel N. Rozner, MD1, Andrea Barbieri, MD1, Marie Robert, MD1, Vikram Reddy, MD, PhD1, Deborah D. Proctor, MD1, Darrick Li, MD, PhD2. P0230 - Idiopathic Myointimal Hyperplasia of the Mesenteric Veins: A Rare Cause of Intestinal Ischemia, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.