Intestinal perforation due to cytomegalovirus infection in patients with AIDS. Intestinal perforation due to cytomegalovirus (CMV) infection in patients with AIDS is the most common life-threatening condition requiring emergency celiotomy in these patients. The authors describe a patient with AIDS with intestinal perforation due to CMV infection, and review 14 additional cases reported in the English-language surgical literature. The diagnostic triad of pneumoperitoneum on x-ray, evidence or history of CMV infection, and AIDS occurred in 70 percent of patients. The most common site of intestinal perforation was the colon (53 percent), followed in frequency by the distal ileum (40 percent) and appendix (7 percent); perforation usually occurred between the distal ileum and splenic flexure of the colon. Colonoscopy, rather than sigmoidoscopy, is recommended as a screening examination in patients with AIDS suspected of having colonic ulceration due to CMV infection. Multiple biopsies of ulcerated tissue should be obtained. Gross and microscopic analyses of involved intestinal tissue reveal the characteristic findings of ulceration and CMV infection. Despite aggressive therapy, the operative mortality rate in patients with AIDS with intestinal perforation due to CMV infection was 54 percent and the overall mortality rate was 87 percent. Postoperative complications occurred in most patients and consisted mainly of systemic sepsis and pneumonia caused by Pneumocystis carinii infection. An increased awareness of this syndrome by physicians frequently called on to manage patients with AIDS is recommended. 