Pedunculated Lipomas in HorsesBy Dr. Bryan Waldridge · September 26, 2012

Pedunculated lipomas are benign fatty masses that originate from the connective tissue of the intestine (mesentery). Over time, abdominal lipomas enlarge and gradually stretch out a stalk of connective tissue that may eventually wrap around the intestine and strangulate it. The small intestine is most commonly involved, but other parts of the intestinal tract can be affected. Strangulated bowel caused by pedunculated lipoma is a surgical emergency.

Pedunculated lipomas are a problem of older horses. Older horses have had more time for the masses to develop, enlarge, and eventually cause problems. Studies have found that horses in their mid to late teens and older are at highest risk. Geldings appear to be more commonly affected than mares and stallions. Breeds shown to be at higher risk include American Saddlebreds, Arabians, Quarter Horses, and ponies.

Surgical correction of pedunculated lipoma involves removal of the lipoma and its stalk, and often requires removal and repair of the strangulated intestine. Occasionally, only the lipoma and its stalk need to be removed. Unfortunately, there is usually a length of intestine that has been irreversibly strangulated and requires removal and reattachment of normal intestine (resection and anastomosis). Survival rates of horses that have had surgery for pedunculated lipoma is comparable to survival for other types of surgical colic.

Studies have not proven an association with excess body fat and the development of pedunculated lipomas. Clinically, both obese and thin horses appear to be equally affected. Like all fat tissue, lipomas will shrink with dietary restriction. However, keeping a horse from becoming obese or restricting dietary intake is not effective to prevent the development of pedunculated lipomas.