Idiopathic myointimal hyperplasia of the mesenteric veins-a report of two cases.

Background: Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a rare condition that poses a diagnostic challenge to surgeons and pathologists alike. Our aim is to describe two cases of IMHMV requiring operative intervention. The challenge going forward is accurately and systematically identifying factors from both a pathologic and clinical perspective that guide timely diagnosis and avoid unnecessary treatment.

Case Description: A 37-year-old male with no significant past medical history was evaluated for a two-month history of abdominal pain, constipation, diarrhea and recent bleeding per rectum. Computed tomography (CT) scan revealed abnormal wall thickening with surrounding inflammatory changes and mesenteric edema involving the descending and sigmoid colon as well as the rectum. The patient was taken to the operating room where he underwent a laparoscopic-assisted extended left colectomy with end colostomy. The patient did well postoperatively and was ultimately meeting all goals for discharge by postoperative day 9. A 49-year-old male with a past medical history of hypertension, gastroesophageal reflux and recent coronavirus disease 2019 (COVID-19) infection was admitted to another hospital following several months of colitis of unknown etiology; unresponsive to antibiotics and steroids. CT scan revealed concentric, severe mural thickening and intramural edema of the distal descending colon extending to the rectum consistent with proctocolitis. The patient was taken to the operating room where he underwent a laparoscopic-assisted low anterior resection with end colostomy with findings of an extremely indurated, thickened left colon and rectum. The patient recovered from these additional interventions and was discharged home in stable condition on postoperative day 32.

Conclusions: A multidisciplinary team approach to this condition will be vital to administering the appropriate treatment modalities for future cases of IMHMV.