Idiopathic Myointimal Hyperplasia of the Mesenteric Veins: Diagnosed After Resection due to Insufficient Palliative Surgery.

INTRODUCTION

Idiopathic myointimal hyperplasia of the mesenteric veins (IMHMV) is a rare, non-thrombotic ischemic bowel disease caused by the proliferation of smooth muscle cells in the venous intima. Most patients are initially diagnosed with typical ischemic colitis or inflammatory bowel disease (IBD) and are treated nonsurgically. There is no established treatment for IMHMV, and surgery is the mainstay of treatment, although the optimal surgical approach remains unclear.

CASE PRESENTATION: A 66-year-old man visited the previous hospital with abdominal pain and was clinically diagnosed with ischemic colitis. Diagnostic colonoscopy showed inflammation from the sigmoid colon to the lower rectum. The biopsy did not reveal malignancy or IBD. His clinical condition did not improve after 2 months of conservative treatment, and he underwent a diverting colostomy. The symptoms temporarily improved, and he was referred to our hospital. However, 1 month postoperatively, computed tomography showed a rupture of the sigmoid colon and fluid collection around the sigmoid colon. He was diagnosed with perforation of the sigmoid colon due to relapse of ischemic colitis and underwent Hartmann's procedure. Histopathological examination showed stenosis and obstruction of the venous lumen at the perforation site with whole-layer necrosis, and proliferation of smooth muscle cells in the venous intima. The pathological diagnosis was IMHMV. He was discharged from our hospital 23 days after surgery without major complications and has had no symptoms or recurrence 8 months after surgical resection.

CONCLUSIONS

IMHMV is a rare disease, infrequently suspected preoperatively and typically diagnosed after surgical resection. Palliative surgery, such as colostomy, may not be a sufficient treatment for IMHMV.