Pneumatosis cystoides intestinalis following intestinal bypass.

Two cases of pneumatosis cystoides intestinalis occurring in the bypassed small bowel following intestinal bypass are presented. These cases and the recent recording of four others in the literature indicate this may be a common association. Etiology of the pneumatosis is unknown, but it is probably related to fecal reflux into defunctionalized bowel with the attendant alteration of bacterial flora.