A 44 year old man with diarrhoea for 6 weeks lost 3 stone in weight and had a colectomy for suspected ulcerative colitis. Evidence of amoebic colitis was found in a biopsy of the resected specimen and motile amoebae were detected in slime from the large bowel remnant. Emetine therapy was commenced but the patient's condition steadily deteriorated; he became jaundiced, semicomatose and died 4 days post-operatively.
There are two specimens. One is a segment of colon 26 cm. long. The other includes terminal ileum, caecum, appendix and ascending colon. On the mucosal surface there are numerous ulcers up to 2.5 cm in greatest diameter in the ascending colon. The ulcers tend to be orientated transversely. They have pale necrotic floors, over-hanging edges, and hyperaemic borders. In the ileum there are several tiny pale nodules 1 to 3 mm in diameter, which are early lesions. This is colitis due to Entamoeba histolytica. At post mortem examination, amoebic abscesses were found in the liver, lung and brain.
Entamoeba histolytica is a parasitic protozon which is transmitted by faecal contamination of food and water. The organism is passed by asymptomatic carriers and can survive in the external environment in an encysted form.