Skin tumors are considered common in dogs and cats. “Common” is a relative term. For a dog, common means that yes, you are very likely to see at least one skin tumor on your dog during the course of their life, no matter what the breed, and you might see a skin tumor on your cat in their lifetime.
The good news is, with early detection and diagnosis, most skin tumors can be cured in dogs. In cats, malignant aggressive tumors are more likely, but here too, with early detection and diagnosis, aggressive veterinary treatments can cure them.
Historically, many pet owners typically “wait to see” if that skin tumor or skin tumor plus lump or bump under the skin grows or changes. This can be very risky and I recommend against it. Good, appropriate, aggressive, and thorough veterinary care more often will involve some form of biopsy when a new skin tumor is discovered on your dog or cat. This is particularly important if:
- Your dog is older (more than 6 or 7 years old)
- The skin tumor grows or changes quickly
- Your dog has had a malignant tumor before
- Your dog is white in color (or mostly white)
- The skin growth is in the groin area
- You live in a really sunny area
- Your pet is acting systemically ill (not eating, vomiting, lethargic)
- Your pet is a cat (any age)
How Common are Benign and Malignant Skin Tumors?
Typically over 80% of all skin tumors on dogs are benign. The most common benign skin tumors are histiocytomas and adenomas. Histiocytomas on young dogs often go away all on their own!
The most common malignant skin tumor found on dogs is the mast cell tumor. The most important thing about a mast cell tumor is that it is “the great pretender” and it can look like anything.
In cats, unfortunately the statistics are almost reversed when compared to the dog. Typically over 80% of all skin tumors on cats are malignant. The most common malignant cat skin tumors are mast cell tumors, squamous cell carcinoma, and fibrosarcoma. With all these malignant tumors, early detection, diagnosis and then treatment is key to a favorable outcome.
What are the Symptoms of Skin Cancer in Dogs and Cats?
Skin tumors can take on a wide variety of looks. Be sure to get your pet checked out if you see any of these changes on the skin:
- Raised nodule or bump that still has hair on it or is hairless
- Non-healing scab (where you thought there might have been just an abrasion but it is not healing)
- Discolored skin – red, black, bluish, bruised looking
- Localized persistent deep flakes or thick skin (skin texture changes)
- Warty looking bump
In some cases, skin cancer will cause subtle skin change in combination with more serious systemic or constitutional signs of illness. These signs or symptoms can include loss of energy, loss of appetite, vomiting, diarrhea, fever, and changes in breathing. If your pet has a skin change plus these signs, be sure to get to your veterinarian or to an emergency veterinarian as soon as possible.
Diagnosing Skin Cancer in Pets
Unlike some illnesses or diseases where making a diagnosis can involve a huge number of different tests, diagnosing a skin tumor starts with some form of biopsy. After a biopsy, if the tumor is found to be malignant, other tests are needed to check for metastasis.
Treating Skin Cancer in Pets
Treatment varies depending on the location and type of tumor but surgery is most often the main form of treatment. As already mentioned, some benign skin tumors go away by themselves! Once surgery is complete, or if for some reason, surgery is not indicated, your veterinarian may recommend consultation with a specialist –specifically in internal medicine or oncology. There are many amazing treatments veterinary specialists can perform that can contribute to a prolonged happy life even after a diagnosis of a malignant skin cancer.
Prognosis for Skin Cancer in Pets
Prognosis varies greatly with the type of skin cancer diagnosed. To make a big generalization, dogs with skin cancer tend to respond better to treatments. We know cats have nine lives, but skin cancer is often a more serious diagnosis with cats and it can sometimes be tough to treat.
Because surgery is often the first step, it is important that all of the tumor is removed. Depending on the location of the tumor, your veterinarian might refer you to a surgical specialist. They have tools and tricks that can help ensure the whole tumor is removed and that healing occurs without nasty complications. Removing an ear (the flap part or pinnae) as an example, might seem extreme for a skin cancer but remember that it can cure your dog and as the fur grows back, often you’re the only one who will notice the ear is missing!