An unusual abdominal mass.

Accepted 20 August 1997 A 78-year old woman presented with pain in her left lower abdomen for three days. She had also noticed an associated swelling in the same area, and a feeling of incomplete evacuation of her bowel. However, there was no nausea, vomiting, change in bowel habits, or rectal bleeding. She was otherwise fit and healthy, apart from mild hypertension for which she was taking bendrofluazide. On examination, she was anaemic and pyrexial. Pulse rate was 90 beats/min and blood pressure 160/85 mmHg. Her abdomen was distended, with no scars, and normal hernial orifices. A tender, smooth, fixed, poorly outlined mass was found in the left iliac fossa. Rectal examination and sigmoidoscopy up to 12 cm were normal. Initial investigations showed haemoglobin 9.8 g/l, white blood cells 10.1 x 109/1, platelets 328 x 109/1, and a normal chest X-ray. Her plain abdominal X-ray is shown in figure 1. An initial diagnosis of diverticular abscess was made, and she was started on antibiotics, clear fluids by mouth and analgesia. Subsequently, she underwent a computed tomography (CT) scan of the pelvis which is shown in figure 2.