Mast Cell Tumours in Dogs

May is Melanoma and Skin Cancer Awareness Month. The media are currently sharing facts about skin cancer, encouraging people to have regular skin checks, and emphasizing the importance of sun safety and skin cancer prevention - especially in Australia, where the sun's UV rays are particularly intense, and skin cancer is a significant health concern. While our pets do not as frequently develop UV-associated melanoma, dogs and cats do develop other skin cancers.

Mast cell tumours, while uncommon in people, are one of the most common skin cancers diagnosed in dogs. It is important for owners to be aware that the appearance of mast cell tumours can be incredibly variable; they might be a small innocuous skin nodule still covered in hair, or a hairless pink skin nodule, or a more darkly-pigmented skin nodule, or a larger more extensive cutaneous mass, or even a non-healing sore.

Mast cells, themselves, store several chemical compounds, including histamine, so these tumours can also be red, inflamed and itchy. Similarly, the biological behaviour of mast cell tumours is quite variable. Statistically, most mast cell tumours in dogs are considered lower grade, behave less aggressively, and can often be successfully managed with surgery alone. However, some mast cell tumours are considered higher grade, and unfortunately display more aggressive behaviour, with a greater risk of metastasis. In these cases, a combination of surgery, radiation therapy and chemotherapy might be considered in the management of the disease process.

Rocky (pictured) underwent treatment for a concerning mast cell tumour last year, consisting of surgery and a course of injectable chemotherapy. At his last recheck, Rocky was doing extremely well and still loving life with his family.

Like Rocky’s diligent owner, if you notice any lumps or bumps on your canine companion, the advice of their regular veterinarian should be sought. And, while we certainly hope your pet never requires the advice or services of the Oncology Service at VSS, if needed, the team is always here to help.