Anytime you find a lump or bump on a pet it is always a cause for concern. It is recommended for each lump to get checked out by your veterinarian. Since you cannot tell if a lump is cancerous just by examining it, they will perform a fine needle aspirate and send the sample to the laboratory. A fine needle aspirate is a technique that collects cells from the lump and those cells are examined under a microscope to determine if they are cancerous or not.
Luckily, many results come back benign (not cancerous) or “fatty” lumps known as lipomas. They usually feel soft, round, and moveable under the skin. Lipomas are tumors that arise from fat cells that grow at a different rate causing a lump. Depending on the rate of growth, lipomas can grow to be very large, but do not invade or destroy other tissues. Your veterinarian may recommend to watch the growth for any changes. It is not unusual to find multiple lipomas and appears to be most common in older and overweight dogs.
There are some instances that lipomas need to be removed. While majority are cosmetic, some lipomas can become bothersome to the pet and cause discomfort or impede movement. Sometimes it is necessary to obtain a biopsy if the tumor changes shape, color, or grows very rapidly. Malignant tumors can be hidden by a massive lipoma or in very rare instances, it could be a liposarcoma or infiltrative lipoma. Liposarcomas are very rare malignant versions of the lipoma and require large surgical excision or sometimes chemotherapy. Infiltrative lipomas are very invasive and invade the surrounding tissues, but do not spread to other parts of the body. Surgery and radiation have been used to treat infiltrative lipomas.
If your pet develops a lump or bump, have it checked out by your veterinarian immediately.