Pets can have cancerous tumors too

Let’s get right to this week’s questions. Q: What can I do to make the most of a trip to the veterinarian?

A: In addition to your pet, there are several items you should take to the veterinarian with you. Bring any records you have for your pet, especially if this is your first visit to the office. Also bring along any over the counter medications, dietary supplements, vitamins, and prescription medications you are giving your pet. These medications and records will help your veterinarian compile a complete medical history.

Have the primary caregiver for the pet attend the visit. It is very difficult to discuss the care and medical management of a pet when the primary caregiver is not present. It is also important to be honest and complete when providing information to your veterinarian. Your pet’s doctor is not going to judge you. He does need to know exactly how your pet is being cared for and everything you have tried on your own. In addition, do be afraid to ask questions. Many people find it helpful to write down a list of questions for the doctor.

For most visits it is appropriate to supply a fresh fecal sample. If there are any issues involving changes in drinking or urination behaviors, please do not allow your pet to urinate on the way into the veterinarian’s office. If a urine sample is required, a full bladder is most helpful. Similarly, if an ear infection or skin problem is suspected, please do not clean the ears or shampoo the pet before the examination.

Finally, keep an open mind. Even if you have owned many pets over many years, medical knowledge advances every day. Recommendations on nutrition, parasite control, vaccination, wellness laboratory testing, and other topics may change from year to year.

Q: What is the most common type of skin mass you see in dogs?

A: Four out of five skin masses in dogs are benign. Although there are dozens of types of benign skin masses, most are either sebaceous cysts or lipomas, commonly called “fatty tumors.”

Sebaceous cysts are generally small, round, firm masses in the skin itself. They move freely with the skin and are usually not painful. Occasionally one will rupture and get infected. Generally these masses are ignored unless they present a cosmetic problem or repeatedly rupture. 

Lipomas are soft, freely movable masses under the skin. They can be small or grow quite large. Small lipomas can be safely ignored. Larger lipomas frequently need removal. The largest I have removed was the size of a basketball.

Cancerous skin masses in dogs are fairly common. Roughly one out of every five skin masses is cancerous or pre-cancerous. The most common type is a mast cell tumor, which account for nearly 15 percent of all skin tumors in dogs. Lymphoma, squamous cell carcinoma, melanoma, and breast cancer are all commonly seen as skin masses in dogs. Many can look quite benign, even to the trained eye, so it is important to have each one checked.

When a new mass appears, it is wise to have your veterinarian perform a needle aspirate of the tumor. This test is quick and relatively painless. The aspirate will allow the veterinarian and/or a veterinary pathologist to review the cell type inside the mass. Together with the clinical appearance, the microscopic appearance will allow your veterinarian to advise you on the best course of action. The needle aspirate is one of the most overlooked tests in veterinary medicine. Many times I have found malignancy in a mass that I had suspected would be benign. In these cases, a quick surgical cure is frequently possible due to early detection.

Q: Do cats get skin cancers too?

A: Yes. Skin masses are much less common in cats. However, when they occur, they are much more likely to be cancerous. On the other hand, cancerous skin masses in cats are generally not as aggressive as cancerous masses in dogs. They also frequently respond better to medical treatment.

The most dramatic exception to this rule is the feline fibrosarcoma. These aggressive tumors are frequently incurable despite extremely aggressive surgery, radiation, and/or chemotherapy treatments. Injections have been shown to increase the risk of these tumors, so any mass detected at an injection site should be examined by a veterinarian immediately. Fortunately, this cancer is uncommon, affecting roughly one in ten thousand cats. It also appears that the incidence is declining.

Dr. Watts is a companion animal general practitioner and owner of Clevengers Corner Veterinary Care. He can be reached through ClevengersCorner.com or by calling 428-1000.