What Do Mast Cell Tumors Look Like?

Mast cell tumors typically appear on the skin and are a result of an abnormality in the body's mast cells. Mast cell tumors can be malignant or benign and can be dangerous if they are cancerous, states Dr. Holly Nash of Doctors Foster and Smith. Therefore, it is extremely important to know what a mast cell tumor looks like to know if a dog may have developed one.

  1. The Facts

    • Mast cell tumors lack a signature look, which can be an issue if a dog has one. There is no set size, shape or color for a mast cell tumor. However, there are common locations in which mast cell tumors can appear. Therefore, if a dog has a mass, a visit to the veterinarian is essential for an examination and biopsy to know exactly what is bothering the dog.

    Size

    • Mast cell tumors do not have a characteristic appearance and their sizes vary. Mast cell tumor can be rather small---about the size of a pea---or large like a quarter. In addition, according to the Mar Vista Animal Medical Center, size changes in mast cell tumors are common, due to the release of granules.

    Shape

    • Mast cell tumors are typically raised, rounded masses, states PetPlace.com. According to Dr. Nash, mast cell tumors can be bumpy or smooth and some are even ulcerated. In addition, the tumors can have one mass or multiple masses.

    Color

    • Mast cell tumors do not come in one color alone, making it impossible to diagnose a mast cell tumor based on the color of the mass. Some tumors can be red, while others can be black. In addition, mast cell tumors are often located under the dog's skin; therefore, the tumor itself cannot be seen, just the swelling under the dog's skin and fur.

    Location

    • While mast cell tumors can appear anywhere on a dog, there are a few places in which they tend to grow. According to Dr. Nash, mast cell tumors often grow on the trunk of the dog, as well as on the limbs and the genital area. If the dog has a tumor in these areas, it does not mean that it is definitely a mast cell tumor; however, it is a possibility. The only way to know for sure is through a biopsy.