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Ask a Vet: Are the Small Lumps On My Dog’s Skin Serious?

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Q: As my dog has gotten older, he’s developed little mole-like growths under his fur. He’s part poodle, and I’ve read this is common for the breed. Our vet isn’t concerned about any of them yet, but what’s your opinion? Are there any telltale signs that a growth like this could be serious?

Dr. Chris Miller, AtlasVet DC: Small lumps and bumps are a certainty for most breeds. In my experience boxers, Labradors, poodles, cocker spaniels and schnauzers are the lumpiest, bumpiest breeds that come to mind. The reality is that any breed is susceptible to a variety of skin or subcutaneous (the fatty layer of connective tissue below the skin) growths. We call these growths “tumors” in the truest sense of the word, meaning “an abnormal swelling.” Most are benign or not problematic, while a few can be rapidly growing malignant tumors that could be troublesome. The trick is deciding which is which. In this specific case, if the growths are small and slow growing they are likely small cysts that are common in poodles. Below are a few things to consider when evaluating small skin masses.

Dogs that are older than seven years of age are much more prone to develop dermal tumors. Your veterinarian sees them on a daily basis and is probably skillful at eyeballing a growth and letting you know if they think one is a problem or not. As a rule of thumb, tumors that are growing rapidly, are irregular in shape, painful or are producing discharge are more likely to be a problem. The most common concern is that the tumor is caused by cancer. However, ruling out other causes like infection, inflammation, and cysts are important in deciding how, or if, to treat the mass. The problem is a veterinarian cannot simply look at a growth and tell you for certain what is causing the problem. Our guesses are usually good, but not perfect.

There are three options when it comes to diagnosing and treating skin growths. If the mass is slow growing and consistent with a benign tumor, veterinarians are quick to implement benign neglect. This basically means that if the tumor doesn’t fit the criteria of a dangerous one, we will simply monitor it. If the tumor is growing rapidly, causing problems, or more information is needed, your veterinarian may perform a fine needle aspirate. This is when a small needle is used to obtain cells from the mass. Some tumors do not give up their cells so easily, and sometimes small tumors can be missed by the needle when obtaining the sample, resulting in a false negative result. For this reason, the most accurate test is a biopsy, in which a piece of the tumor itself, or ideally, the entire tumor is removed and sent in for evaluation by a pathologist. While this is a more expensive and invasive option, the information obtained will let us know what kind of tumor is present and if the entire tumor has been removed on a microscopic level. When your veterinarian knows exactly what the mass is, better decisions can be made about treatment and prognosis.

Deciding how to manage dermal growths on a dog can be difficult, especially in a predisposed breed or an aging dog that has multiple masses. Testing each mass can be expensive, but in a predisposed breed it may be worth it. Discussing your pet’s risk factors with your veterinarian can help you make an informed decision about whether to wait and watch, or to schedule a procedure to remove a potentially dangerous skin mass.

Find Dr. Chris Miller on Twitter at @DCVet.