Mast Cell Cancer in Old Dogs

Mast cell tumors, also called mastocytomas, often occur in senior dogs, usually 8 to 9 years old. Mast cell tumors can be benign or malignant and, therefore, should receive evaluation from a veterinarian as soon as they are suspected. Fortunately, some tumors can receive treatment if detected early enough.

  1. Facts

    • Mast cell tumors occur on mast cells, states the Natural Pet Health Remedies website. Mast cells are a part of a dog’s immune system and release histamine, heparin and enzymes that break down protein when attempting to defend the body against invaders such as parasites. Mast cells are located in the intestine and the respiratory system and do not circulate throughout the body.

    Symptoms

    • Mast cell tumors are often hard to identify because their appearance varies. Some tumors are large, while others are small. The tumors can appear bumpy, smooth or even ulcerated. Mast cell tumors may cause your senior dog to scratch at his location sites and the areas may bleed as a result. If the tumors are not located on the skin, but rather the intestine, the dog may vomit or have blood in its stool as a result of ulceration in the intestine from the tumor. In addition, the dog may vomit or have abdominal pain, states Dr. Jeffrey Philibert of the Pet Place website.

    Risks

    • According to the Natural Pet Health Remedies website, about half of all mast cell tumors are malignant, or cancerous. In addition, about 50 percent of removed tumors come back. Mast cell tumors can appear anywhere on your senior dog, but tumors that are present in the armpit, groin, lips, eyelids, mammary tissue, anus and genital areas are likely to be malignant.

    Diagnosis

    • Your veterinarian can determine if your senior dog has a mast cell tumor by a few methods. The vet can insert a needle into the tumor to collect cells. Those cells are then viewed under a microscope to determine if they are mast cells. If this is not an option, the doctor can surgically remove the tumor and send what is collected to a laboratory for a biopsy. The vet may also take blood and urine to monitor the dog’s organ functions, states Philibert.

    Treatment

    • Treatment of mast cell tumors often consists of removing the mass surgically. The veterinarian takes wide margins to remove as many cells as possible. This surgery is often risky, though, because the tumor can release its substances into the dog’s body during removal, which can have harmful effects on its heart. The veterinarian may also prescribe chemotherapy and radiation in an effort to prevent the cancer from spreading and reoccurring.