Diseases of the small intestine account for approximately 34% of all colic cases treated at veterinary hospitals. Most (up to 85%) are caused by strangulations, which disrupt blood supply to the small intestine. The most common small intestinal strangulating diseases in adult horses are caused by pedunculated lipomas.

What is a Pedunculated Lipoma?

A pedunculated lipoma starts as a discrete plaque of fat within the mesentery of the small intestine. The mesentery is a broad but thin sheet of tissue that attaches the small intestine to the roof of the abdominal cavity and contains the critical arteries that provide life-sustaining oxygen to support normal intestinal function. As the horse gets older, the lipoma progressively enlarges and thereby stretches its attachment to the mesentery to form a long cordlike structure called a pedicle. The pedicle then wraps around a segment of nearby small intestine and its mesentery like a South American bola to strangulate these tissues until they die.

Lipoma development takes time, which explains why most affected horses are 10 years and older at the time of diagnosis. Old age is therefore an immediately recognizable diagnostic clue to strangulating lipoma. Unfortunately, affected horses are also victims of a diagnostic distraction: their own stoic attitude that blunts development of the more severe signs of colic