B-cell multicentric lymphoma as a probable cause of abortion in a Quarter horse broodmare.

A 5-year-old Quarter horse broodmare was evaluated for inappetence, depression, and diarrhea 13 days after aborting a 9-month gestation fetus. Clinical and laboratory examination ruled out uterine rupture and peritonitis. Ultrasonography of the uterus combined with cytological analysis of peritoneal fluid suggested the existence of diffuse lymphoma. A multicentric B-cell lymphoma involving the uterus and ovary was confirmed at necropsy and histopathological examination.