Pneumatosis coli with ulcerative colitis as a rare complication of colonoscopy.

Pneumatosis coli is a relatively rare condition characterized by the presence of gas in the submucosa or subserosa involving mainly the large intestine and, occasionally, the mesenteric attachments. We experienced two cases of pneumatosis coli with ulcerative colitis after colonoscopy that had different clinical courses. Case 1 showed submucosal pneumatosis coli and portal venous air. The air was resolved 30 h later. Case 2 showed subserosal pneumatosis coli and retropneumoperitoneum. The air was eliminated after 3 weeks. The clinical features of pneumatosis coli may depend on the intramural region of the air. Cases 1 and 2 had different air localization, that is, submucosal and subserosal air, and this seems to reflect the differences in the complications. In Case 1 the air expanded to the portal vein, and took only a short time to resolve. In Case 2, however, the air leaked to the retroperitoneal space and took a long time to resolve. In summary, pneumatosis coli as a complication of colonoscopy presented different features depending on the air location. To our knowledge, this is the first report to reveal the difference of air localization and the complications associated with pneumatosis coli after colonoscopy.