A 69-year-old woman was admitted to the hospital because of recurrent pain in the right lower abdominal quadrant and radiographic evidence of a cecal abnormality.The patient had been well until 44 days earlier, when fever and pain in the right lower quadrant developed, without nausea, vomiting, or diarrhea. Two days later she was admitted to another hospital. The white-cell count was 16,600 per cubic millimeter; the bilirubin level was 2.4 mg per deciliter (41 m mol per liter); other tests of liver function were negative. A Gastrografinenema examination showed that the colon was normal except for considerable spasm of the cecum and an extrinsic mass effect along its lateral aspect (Fig. 1). No diverticula were seen, and the terminal ileum was normal. An intravenous urographic examination was negative, except for very slightly delayed excretion by the right collecting system. A computed tomographic (CT) scan of the abdomen showed calcification of the aorta and a few granulomas in the spleen. There was circumferential thickening of the cecum, with surrounding pericolic stranding (Fig. 2). The small bowel was normal, and no lymphadenopathy was detected. No oral intake was allowed, and antibiotics were given intravenously. The patient's condition improved rapidly, the white-cell count became normal, and the bilirubin concentration decreased. She was discharged.The patient subsequently felt well and ate normally, without abdominal pain, fever, constipation, hematochezia, or weight loss, until two weeks before admission, when mild pain recurred in the right lower abdominal quadrant. Two days before admission diarrhea developed. On the following day treatment with ciprofloxacin and metronidazole was begun, andThe New England Journal of Medicine Downloaded from nejm.org at UNIVERSITY OF GEORGIA on August 11, 2015. For personal use only. No other uses without permission.