Mast Cells in Dogs

Mast cells are present on the skin, intestines and other tissues, being produced by the immune system. The overgrowth of these cells will result in a mast cell tumor, which is a common type of skin cancer in canines. However, the tumors may also be benign.

Mast Cells in Dogs

The mast cells are part of the immune system and are present on the skin and other tissues in the body. The cells have an important role in the defense of the body.

When examined, these cells will have a content of:

  • Heparin
  • Histamines
  • Proteolytic enzymes, used by the body to assimilate proteins

These substances will defend the dog’s system, being toxic for parasites, bacteria and other infectious agents.

Mast Cell Tumors

Approximately 1 in 5 dogs with skin tumors are affected by a mast cell tumor. These tumors may affect dogs of all ages, but preponderantly, dogs over the age of 8 present such tumors.

Some breeds are also more prone to developing this type of tumor (i.e. Boxers or Bulldogs).

Types of Mast Cell Tumors

The mast cell tumors may be benign or malignant and forms due to an overgrowth of mast cells.

The benign tumors are not life threatening and shouldn’t be removed, as the histamines, heparin and enzymes present in the mast cells may be discharged into the dog’s system and may cause complications including:

  • Increased heart rate
  • Hypertension
  • The incision site may take a long time to heal

However, if the benign tumor affects the dog’s functions, it should be removed. If detected early enough, the malignant tumors can be removed and the dog will have high chances of leading a cancer free life.

Detecting Mast Cell Tumors

Mast cell tumors may be located anywhere on the dog’s skin. The tumors may vary in appearance (i.e. smooth, rough or ulcerated) and may also be subcutaneous.

You should check with your vet when you notice any growth on your pet’s skin. A biopsy will determine the nature and the composition of the tumor. The vet will determine the grade and the stage of the tumor.

Grades of Mast Cell Tumors

The grading indicates how malignant the tumor is:

  • Grade 1 mast cell tumors are considered benign
  • Grade 2 may affect the subcutaneous tissues also and may be malignant
  • Grade 3 are clearly malignant and will affect deeper layers of skin and even neighboring organs and tissues

Stages of Mast Cell Tumors

The stages of the malignant tumors will establish the type of treatment that may be administered:

  • Stage 0 is a tiny tumor that doesn’t involve any neighboring tissues and lymph nodes
  • Stage 1 is a small tumor, but the lymph nodes are not affected
  • Stage 2 is when the cells have spread to the nearest lymph nodes
  • Stage 3 involves the formation of several tumors that spread to other organs
  • Stage 4 is metastasis and may affect the lymph nodes and the lungs

The tumors that are staged 0 to 2 may be removed through surgery. In stage 3, the vet may determine if surgery is still possible. In the last stage, only medication treatment is possible and the dog has low chances of surviving for more than 6 months.