The natural course of Clostridium perfringens--induced pneumatosis cystoides intestinalis.

Primary pneumatosis cystoides intestinalis (PCI) is an uncommon, usually benign condition whose natural course is poorly understood and which can sometimes produce significant changes in a patient's cecum and sigmoid colon. In this study, PCI was produced by monocontaminating the peritoneal cavities of adult germfree rats with Clostridium perfringens. These animals were then observed for up to 26 weeks. PCI took up to two weeks to develop, lasted at least ten weeks in most animals, and presumably disappeared from 42% of 26 animals killed during the final 16 weeks. PCI was usually benign, but in some animals produced extensive and persistent subserosal and submucosal air cysts of the cecum and sigmoid colon without evidence of intra-abdominal sepsis. These profound segmental colonic lesions suggest a possible etiology for other segmental inflammatory bowel diseases.