Lumps and Bumps!
You’ve probably noticed that many dogs (and occasionally cats) frequently have new growths that will sprout up on their skin. How concerning are these and what are the best steps for learning more? Let’s cover some FAQs in regards to these:
1) Why is my dog lumpy?
-The short answer is that we don’t know. The production of lumps and bumps is generally unrelated to diet, medications or other illnesses. Some breeds can be more predisposed to developing certain types of benign and cancerous tumors, but really any dog is capable of developing any type of mass.

2) Are all masses cancerous?
-Fortunately, no! There are many types of benign growths that exist. Some of these have very distinct looks that we can diagnose with a glance, such as papillomas (warts), sebaceous adenomas (glandular growths) and skin tags. Other types might require additional testing, but can still turn out to be benign. These include lipomas (fatty tumors), cysts, and other benign versions of tumors.

3) How can you tell if a mass is cancerous?
-Here’s the short answer: You CANNOT tell by looking at it alone (perhaps with the exception of most warts and skin tags). This is why we often recommend a needle aspirate to assess the types of cells present within a mass.

4) What are some signs that might indicate a more aggressive mass?
-Generally speaking, a fast-growing mass is a concerning mass. Anything that’s doubling in size in less than a month should be evaluated by a veterinarian. Masses that seem to be well-adhered to underlying muscle tissues (ie. non-moveable) or that feel particularly firm are also more frequently concerning. Size is not always a good indication of aggression, as many large masses can turn out to be benign and many small masses will end up being cancerous.

5) How does my veterinarian test the masses?
-The first step is in evaluating a mass is called aspiration, meaning we poke it with a needle to get a sample of cells. We then evaluate these cells under the microscope and determine whether the cellular contents are concerning. There are limitations with this process. For examples, it usually doesn’t tell us exactly what type of tumor is present or whether it’s malignant. But it can usually give us a good indication whether the mass needs to be evaluated further or removed altogether for biopsy.

6) What is biopsy?
– While the cellular aspirate is simply a needle poke that can be done during an office visit, the biopsy requires cutting a large section of the tumor out, or potentially removing the entire tumor altogether. Biopsy usually requires sedation or general anesthesia. It will also give a lot more information. We send these tissues out to a laboratory to evaluate them microscopically. A biospy will tell us what type of tumor it is and whether it’s cancerous. In the case of removing a mass, biopsy will also tell us whether we removed the entire tumor successfully, as some cancer cells can spread to the tissues surrounding the mass. We need to know whether any cancer cells were left behind so that we can decide whether further action is needed (ie. additional surgeries, radiation or chemotherapy).

7) Should every mass be removed?
-Not always. Benign masses are frequently left alone as long as they’re not causing discomfort, inflammation or mobility problems in the animal.

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