Lipoma removal surgery is one of the most common procedures done in an animal hospital. Seldom seen in cats, lipomas are non cancerous deposits of fat that seem to have an arbitrary placement anywhere in the animal's body. Most commonly occurring under the skin and attached loosely to the dog's muscle or fascia layers, lipomas rarely cause any physical problems. However, unpredictably they can grow to tremendous size; they can inhibit movement if they grow in highly moveable areas such as in the axillary areas (armpits), or can become irritated if frequently traumatized. On very rare occasions a lipoma may become malignant Click to enlarge: Tissue and Formalin vial for submission to pathologist. and invade local areas as well as metastasize throughout the body. This very dangerous type of lipoma is called an infiltrative lipoma. Many veterinarians will send in any tissue sample removed from a patient in order to get a histopathology report. By having a trained pathologist look at the tissue under the microscope a definitive diagnosis can be made.
Whenever you suspect that your dog (or cat) has a lump, even if it is small and causes no pain, you should have it examined by a veterinarian. Careful evaluation, and even needle biopsy of the mass, will help establish if the lump really is a lipoma. Sometimes they need to be removed before they become excessively large in size. Many grow to about the size of a walnut and never change and cause no medical trouble. Others, as in the surgical example displayed here, need to be removed when it is determined that the lipoma seems to be growing persistently. Below are images of the removal of a large and a small lipoma.