CT appearance of acute abdomen as initial presentation in lymphoma of the large and small bowel.

Computed tomography (CT) is playing an increasingly greater role as the initial diagnostic imaging modality for acute abdomen. Abdominal pain is the most common presenting complaint for intestinal lymphoma, and acute abdomen is a not infrequent admitting complaint. We present the CT findings of five patients with intestinal lymphoma whose initial complaint was acute abdomen. Of these five patients, four had an identifiable mass that was located in the right lower quadrant, with the fifth patient having no identifiable mass on CT. The average mass size was 7.8 cm. Three of the patients showed involvement of the colon only, and two showed involvement of the small bowel only, with acute abdomen in only one of the patients with small-bowel involvement being due to direct extension from mesenteric lymph nodes. Pneumoperitoneum and free intraperitoneal fluid were seen in two patients. It is important, therefore, that the radiologist be aware that one of the causes of acute abdomen with primary bowel involvement is lymphoma, which can simulate appendicitis or diverticulitis in its presentation clinically and by physical examination.