Dr. Joanna Bronson
Sometimes that little lump or bump starts to feel different. It may be nothing or it may prove to be a more serious threat to your pet’s health. This is the time to schedule an appointment with your veterinarian.
However, before you make that date, ask yourself these questions:
- Did the lump or bump show up suddenly?
- If it has been there for a while, has it changed in any significant way?
- Is it harder, has the color, shape, or size changed?
- Is your pet acting normally, or has his behavior changed?
- Is he reluctant to have you touch the spot?
- Were you and your pet anywhere he could have been bitten by a bug or has he had an allergic reaction before such as breaking out in hives?
These are the questions your veterinarian will ask to get a history of the bump.
Mast cell tumors are a common form of skin cancer in pets.
Mast cells are a type of white blood cells that is found in many body tissues. They are allergy cells that play a role in the allergic response to an allergen. Their job is to release chemicals and compounds, (among those being histamine) which causes itchiness, sneezing, and runny eyes and nose. This process of defense is called degranulation.
The problem with mast cells going rogue happens when excessive amounts (called mass degranulation) are released. This mass exodus can cause anaphylaxis, a serious life-threatening allergic reaction.
A mast cell tumor is composed of mast cells. These form as nodules or masses in the skin and can also form internally in the spleen, liver, intestine, and bone marrow. The most common tumors are skin tumors and most affected dogs display a singular tumor.
Since mast cells are always present in the body, the cause for their transformation is not usually a singular factor. Most seem to be caused by a mix of risk factors, some of which are environmental and some are genetic or hereditary.
We do know that certain breeds seem to have a greater risk for the development of these tumors. Among those breeds are Boxers, Bull Terriers, Boston Terriers, and Labrador Retrievers.
The difficulty in noticing these tumors is that they vary in appearance and can show up anywhere on the body. They can be described as a raised lump or bump on or just under the skin. They may be red, ulcerated, or swollen. Some may stay the same for months, and some may appear suddenly and grow very quickly. They may also change size daily as the surrounding skin reacts to agitation from degranulation.
Mast cell degranulation can release chemicals and compounds into the blood stream and affect the internal organs. Ulcers may form in the stomach or intestines and cause vomiting, loss of appetite, lethargy, and Melena (black, tarry stools an indication of internal bleeding). Some cases cause enlarged lymph nodes, and spleen and liver complications that can lead to fluid build-up in the abdomen, making the belly to appear rounded and swollen.
This information is very scary and the only way to know for sure if your pet is suffering from a MCT (Mass Cell Tumor) is typically through a fine needle aspiration where a needle is inserted directly into the tumor and a cell sample is suctioned and examined under a microscope. In aggressive cases, a surgical tissue sample (a biopsy) can provide a more definitive diagnosis.
The pathology report can access the aggression of the cancer and determine if it has or might spread to other parts of the body.
The prognosis is less favorable if the dog is from one of the susceptible breeds, the MCT is located at a spot where the mucous membranes are next to the skin (such as in the gums), and when examined under the microscope, the number of cells that are replicating is high.
The good news is that MCT’s are one of the most treatable types of cancers, if they are labeled as low-grade. Surgery is the best option if there is no evidence of spreading. In high-grade cases, even with no evidence of spread, surgery combined with chemotherapy is recommended. Radiation therapy is another treatment option.
Not all MCT’s are treatable, other factors to consider are the location of the tumors, the age of the dog, and the expense of the treatment.
An early examination can help determine the best course of action for any treatment plan.
— Dr. Joanna Bronson of Bronson Veterinary Services, located at 452 W. Central Road, Coldwater. Contact her at 517-369-2161 or visit bronsonvetservices.vetstreet.com.
