Understanding Mast Cell Tumors in Dogs

Mast cell tumors dogs develop are very common and can occur in any breed. There is not much know about mast cell tumors and why they develop because mast cell tumors typically only happen in dogs, not in humans or cats. Identifying a mast cell tumor early is key to a dog's prognosis. Mast cell tumors are usually cutaneous which means they are on the skin, not growing inside the dog's body. This can make them easier to identify and seek treatment for.

Defining a Mast Cell Tumor

A mast tumor is a collection of mast cells that form a tumor on the skin. Mast cells themselves are cells, which provide needed chemicals to a dog's body. The chemicals include heparin, histamine and serotonin. Mast cells are important to a dog's immune system too, but when a mast cell tumor forms on a dog's body it can produce too many of these chemicals, which can have negative effects on the dog.

Where Mast Cell Tumors Develop

Mast cell tumors can develop anywhere on a dog's body, but often the tumors develop on the skin and are quite noticeable. Skin tumors in dogs are 20% mast cell tumors. Mast cell tumors can also develop in the spleen, liver and bone marrow. Mast cell tumors also develop in the limbs with 40% of mast cells on dogs' limbs occurring in the hind legs.

Grades of Mast Cell Tumors

Mast cell tumors come in three different grades. The grades are determined by carefully examining the cells in the tumor microscopically. The amount of cell differentiation in a tumor, determines the grade of the tumor. Grade 1 tumors are very treatable and contain well-differentiated cells. Tumors with moderately differentiated cells are grade 2 tumors. Grade 2 tumors may or may not respond to treatment. Grade 3 tumors show very little differentiation in cells and grade 3 tumors are more aggressive and likely to spread.

Treating Mast Cell Tumors

Canine lymphoma treatment comes in many varieties. In grade 1 mast cell tumors treatment is typically surgical removal of the tumor with no further treatment required. Grade 2 tumors may respond to surgery and other forms of treatment like chemotherapy and radiation. Grade 2 tumors are more difficult to treat because they are more likely to metastasize or spread throughout the dog's body. Grade 3 tumors can be treated with surgery, chemotherapy and radiate, but because they are aggressive tumors, the treatment many not be effective.

Depending on where the tumor develops on a dog, surgery may or may not be a viable option. Some forms of canine mouth cancer that are determined to be mast cell tumors will cause poor quality of life for the dog if operated on. However, mast cell tumors on the skin, if caught early, often have a positive prognosis requiring no further treatment beyond the initial surgery to remove the tumor.