Canine Mast Cell Cancer

Canine mast cell tumors are common skin tumors. The tumors may be benign or malignant. If the tumor is malignant, the cells are cancerous. A dog with mast cell cancer should be kept under treatment. In some cases, surgery is possible and the tumor may not grow back. In other cases, the tumor can grown and spread to other organs in the dog’s body, which leads to a life threatening condition.

What Are Mast Cells?

Mast cells are typically present in the skin or other tissues in the body, being a part of the immune system of the dog. Mast cells are made up of:

  • Histamines
  • Heparins
  • Proteolytic enzymes, which help the assimilation of proteins

Mast cells are used as part of the defense mechanism of the dog to attack intruders such as parasites or toxins. A tumor is formed when several mast cells are gathered.

Causes of Mast Cell Tumors

There are several theories regarding the cause of the mast cell tumors, but they are still speculative. The tumors may be hereditary, but may also be caused by viruses or influenced by the type of environment the dog lives in.

Canine mast cell tumors can occur in all breeds, but some breeds are more prone to developing these (i.e., Boxers, Bulldogs). Most dogs with mast cell cancer are older, typically over the age of 8.

Symptoms of Mast Cell Tumors

A mast cell tumor can be benign or malignant (cancerous). The majority of these tumors will occur on the limbs, trunk or genital area. The tumors look like bumps and can be on or under the skin. In some cases, the bumps may be ulcerated.

Some clinical signs of cancerous tumors include:

These symptoms occur due to the release of the histamines and heparins that are present in the mast cell tumors.

Diagnosing Mast Cell Cancer

A biopsy is necessary to establish if the mast cell tumor is malignant or benign. The tumor may also be graded (1 to 3, 1 being benign and 3 being more serious).

The vet may also run a few additional blood tests and possibly some x-rays to establish if the cancer has spread to other organs in the body. The stage of the mast cell tumor must be determined to see if its removal is possible. The stages of the tumor may be 0 to 4, 4 being metastasis.

Treatment of Mast Cell Tumors

The treatment may vary according to the grading and the stage of the cancer. Typically, mast cell tumors are removed surgically, but this means that the lymph nodes are not yet affected by the cancerous cells (stages 0 to 2).

If surgery is not possible, radiation therapy can be applied. Radiation therapy can also be effective after surgery to prevent the recurrence of tumors.

If the tumors have spread, radiation may not be effective, so chemotherapy is recommended. Chemotherapy can stop the cells from reproducing and may keep the cancer under control.

However, if the cancer is in metastasis, the disease will be fatal.