A Rare Cause of Progressive Constipation, Abdominal Distension, and Weight Loss

Abstract

A 46-year-old man was referred for evaluation of a 1-year history of progressive constipation, bloating, and 40-lb weight loss. These symptoms had previously been attributed to Crohn’s colitis, but improvement was not achieved after several months of adalimumab. Computed tomography enterography demonstrated prominent distal small bowel dilation with several short segment strictures, bowel wall thickening, and mucosal hyperenhancement (Figure A, arrow). Laparotomy was pursued for surgical management of the strictures. Intraoperatively, the small bowel was massively dilated up to 15 cm, notably uncharacteristic for Crohn’s-associated strictures (Figure B), and full-thickness small bowel biopsies were obtained. Histologic review with smooth muscle actin (Figure C, arrows) and smoothelin staining (Figure D, arrows) demonstrated myocyte degeneration from the inner and outer layers of the muscularis propria, without features of neural degeneration or Crohn’s disease. Based on these clinical and histologic features, a diagnosis of degenerative leiomyopathy complicated by intestinal pseudo-obstruction was established. Postoperatively, adalimumab therapy was discontinued and the patient was initiated on prucalopride and a regulated bowel regimen with complete symptomatic resolution. This case highlights the importance of pursuing additional testing in the setting of discordant findings.