Mast Cell Tumors in Dogs – Know Your Dog's Lumps and Bumps

Canine mast cell tumors are among the most common tumors in dogs and are the most common type of skin cancer found in dogs. I did not realize this until I experienced it first hand with my dog, and started doing extensive research on the topic.

My dog ​​had a really small lump on her head. At first it did not grow at all, so I did not think much about it. All of a sudden it started getting bigger and doing so fairly quickly. That's when I decided to take her in to the vet to have it looked at.

The vet did a fine-needle aspirate, and to my dismay, it came back as a mast cell tumor. Fortunately other tests showed that it had not metastasized. So we quickly got her in for surgery to remove it. When she was under, they did a full body check and found 2 others on her body. When she was done, she looked like Frankenstein, but the cancer had not spread beyond the tumors!

Mast cells are part of the immune system and found through the body. They release chemicals such as heparin, histamine, and proteolytic enzymes when needed to aid with inflammation and allergies. A canine mast cell tumor is a mass of these cancerous mast cells.

Although the cancerous aspect of mast cells is of concern, it's actually the chemicals that are released from them that are the greater concern. When released in normal amounts, these chemicals are vital to normal body function. However, when released in excess, these chemicals are very dangerous, causing:

  • gastrointestinal ulceration (open sores)
  • internal bleeding
  • intestinal allergies

These tumors can have varying appearance. They can look like a raised pink lump, a soft subcutaneous lump, an ulcerated skin mass, and a soft nodule often mistaken for lipoma, which is what I thought my dog ​​had.

As with my dog, several mast cell tumors can develop. They each act independently of the other. So, one could be very slow growing and fairly innocent, while another could be very aggressive.

Unfortunately, the only way to diagnose a canine mast cell tumor is by a needle aspirate. If it is determined that it is a mast cell tumor, than a biopsy will be done to determine the grade of tumor, which then determines the course of treatment. There are 3 grades of canine mast cell tumors. Grade 1 and a less advanced grade 2 treatment is to surgically remove the tumor. With more advanced grade 2 and grade 3, radiation and / or chemotherapy is the recommended treatment.

I have gotten benign cysts in the past, and I chalked that up to what my dog ​​had. Do not make the same mistake I did. I was a basket case waiting for the results to show if it had metastasized or not. The whole time I was thinking that by waiting I increased her risk of a spreading cancer. NOT a good feeling to have!

Do routine checks on your dog so you will know what is normal and not normal. If you feel something, take your dog in and have your vet look at it and diagnose it properly. This article is not meant to scare anyone, dogs are very prone to tears and bumps and there are several out there that are completely benign. It's just nice to be better informed when making decisions for your fur kids.