Small intestinal adenomatous polyps resulting in chronic obstruction in a 3-year-old Quarter Horse gelding

A 3-year-old, Quarter Horse gelding was admitted to Kansas State University Veterinary Health Center with a primary complaint of colic. The horse had a 3-month history of recurrent colic and progressive weight loss. On physical examination, the horse was quiet, alert and responsive. The horse's mucous membranes were pink and capillary refill time was 2 s. His rectal temperature was 37.6°C (99.6°F), heart rate was 56 beats/min and respiration rate was 16 breaths/min. Rectal palpation revealed an approximately 5 cm dilated, firm, tubular, mass traversing from left caudal abdomen to mid abdomen. Nasogastric intubation obtained 6 L net reflux. A 5 cm diameter small intestinal intraluminal mass was detected by abdominal ultrasound. Complete blood count, serum chemistry and peritoneal fluid analysis were performed and all results were unremarkable. The horse was humanely euthanised due to pain and financial constraints. Post-mortem examination and histopathology revealed a 15 × 5 × 5 cm polyp with multiple smaller satellite polyps that obstructed the distal duodenum. Colic was considered secondary to small intestinal obstruction and luminal distension caused by the adenomatous polyps. To the authors’ knowledge, this is the first report to include ultrasound images of a small intestine adenomatous polyp that caused small intestinal obstruction and colic in a 3-year-old horse.