A cat with chronic diarrhea was diagnosed as having duodenal lymphosarcoma on two separate sets of endoscopic biopsies. Prednisolone failed to effect any clinical improvement. However, feeding the cat with a hypoallergenic diet resulted in long-term (i.e., six months) resolution of clinical signs. Most clinicians are familiar with the possibility of mistakenly diagnosing inflammatory bowel disease when the patient has lymphosarcoma; however, this case had the opposite problem: lymphosarcoma was diagnosed histologically on two separate occasions when inflammatory bowel disease was the problem.
