Mesenteric phlebosclerosis: a new disease entity causing ischemic colitis.

Nonthrombotic stenosis or occlusion of the mesenteric veins is a rare cause of intestinal ischemia. The aim of this study was to describe a new disease entity causing chronic ischemic colitis.Seven patients were diagnosed as having mesenteric phlebosclerosis. All seven patients had calcifications in the small mesenteric veins and their intramural branches. No evidence of vasculitis or portal hypertension was recognized. None of the patients had a history of gastrointestinal disease or of prolonged drug use. We report clinical, laboratory, radiographic, endoscopic, and histopathologic findings.Clinical findings included abdominal pain and diarrhea of a gradual onset and chronic course. A positive fecal occult blood test and mild anemia were often found. The patients had linear calcifications and stenosis in the right colon, which were discovered by plain abdominal radiography and barium enema, respectively. Endoscopic findings included edematous, dark colored mucosa and ulcerations. Four patients underwent a subtotal colectomy because of persistent abdominal pain or ileus. The histopathologic findings were macroscopically characterized by a dark purple or dark brown colored colonic surface, the swelling and disappearance of plicae semilunares coli, and marked thickening of the colonic wall, while they were microscopically characterized by marked fibrous thickening of the venous walls with calcifications, marked submucosal fibrosis, deposition of collagen in the mucosa, and foamy macrophages within the vessel walls.These peculiar lesions have not previously been fully described. The cause and pathogenesis still remain unknown. We conclude that such lesions represent a new clinicopathologic disease entity and propose the term "idiopathic mesenteric phlebosclerosis."