The 5 Types of Round Cell Tumors in Dogs

Round cell tumors are among the most common skin tumors that develop in dogs. They are generally subcutaneous, meaning that they develop just below the skin. Keeping track of these tumors is an important way of monitoring your pet's overall health and preventing cancerous growths from spreading. Caught early on, these cancers can be removed easily and will generally not prove to be life threatening. However, you must be knowledgeable about the tumors themselves so that you can act quickly upon the first detection.

1. Mast Cell Tumors

The most common type of round cell tumor is the mast cell tumor. This type of tumor accounts for roughly one quarter of all of the skin tumors that develop in dogs, and it usually strikes dogs that are older than 8 years of age. Certain breeds (namely, those that are descended from bulldog lines) have a much higher rate of tumor growth of this type. These tumors generally develop on the skin of the abdomen and stomach, as well as the back. However, they have been known to grow on internal organs as well. Other signs of mast cell tumor growth include gastrointestinal distresses like vomiting, diarrhea and general nausea.

2. Histiocytomas

Histiocytomas are generally benign types of tumors that grow on the head, neck, legs and feet. They are much less common than mast cell tumors and tend to be smaller as well. They may develop in dogs of any age or breed. In most cases, these tumors mustbe removed because of comfort and mobility issues, and because it can be difficult to determine whether a given mass is a benign histiocytoma or a potentially malignant growth that appears to be similar.

3. Plasmacytomas

Small, red and raised bumps that generally appear on the paws and face, plasmacytomas are potentially malignant growths that tend to occur on older dogs. There is a slight predilection toward male dogs over female dogs when it comes to the development of plasmacytomas. Cocker Spaniels are much more inclined to develop these growths than any other single breed of dog.

4. Transmissable Venereal Tumors

Transmissable Venereal Tumors, or TVTs, are sexually transmitted growths that pass easily between dogs that are sexually active. These tumors are a severe problem in some areas where there are free roaming dogs. TVTs are characterized by small, cauliflower-like lesions that develop around the genitals, nose or mouth. They are bright red in color and can hemorrhage or bleed if rubbed or disturbed. Although these tumors are generally spread through sexual contact, they can also be transmitted through other social behaviors like sniffing and rubbing.

5. Cutaneous Lymphoma

A rare version of the relatively common cancer known as lymphoma, cutaneous lymphoma tends to strike dogs that are middle aged or older. It's distinguishable from these other round cell tumors because it usually develops as multiple masses. Dogs with a history of skin disease are at increased risk.