Introduction: Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a rare condition affecting young males and is characterized by proliferation of intimal smooth muscles and hyperplasia of the mesenteric veins, and affects the rectosigmoid region. Clinically and endoscopically it mimics inflammatory bowel disease (IBD) with the biopsy showing features of ischemic colitis.
Case Description/Methods: We present a case of a 52 year-old male with a history of IDDM and hypertension who presented with the complaints of cramping lower abdominal pain, rectal urgency and foamy mucous like diarrhea following a screening colonoscopy. On presentation, he had stable vital signs. Physical exam revealed left lower quadrant tenderness without peritoneal signs. Pertinent bloodwork showed a normal white count, CRP and ESR. CT scan of the abdomen and pelvis showed diffuse wall thickening from the distal descending colon to the rectum consistent with colitis. Colonoscopy showed congestion of the mucosa and biopsies were consistent with ischemic colitis. CTA of the abdomen and pelvis failed to show significant large vessel disease. He was given a trial of high dose prednisone and rectal mesalamine for the working diagnosis of IBD without improvement in symptoms. Patient underwent rectal wall biopsy which showed acute ischemic injury. Subsequently, he underwent left partial colectomy for ischemic bowel. Pathology showed diffuse myointimal proliferation of mesenteric veins with luminal obliteration, acute and chronic inflammation, fat necrosis of surrounding adipose tissue and a viable muscularis propria. Fibrinoid necrosis of mucosal vessels were noted. These changes were consistent with IMHMV with secondary ischemic necrosis and were confirmed through Elastin and Desmin stains. Patient symptomatically improved following the bowel resection.
Discussion: IMHMV should be suspected in young males presenting with proctosigmoiditis when biopsies are not consistent with IBD and symptoms fail to improve with standard therapy. With more awareness, IMHMV may be identified prior to complications such as ischemic bowel which necessitate surgical intervention. Currently there is no treatment for IMHMV, but as the pathogenesis is better understood with wider reporting, hopefully better treatment options will become available. As of now, resection of bowel appears to be curative.
