Hi Corinne,

Thanks for your question and sending in the image of this mass-like lesion. The most important thing to know is that there is not a doctor in the world that can definitively diagnose what a mass is by looking at it. So at this point, I need to make the statement that any assumptions I make cannot be relied upon but I can certainly give you some guidance.

The first thing we have to do is identify the mass. The way we do this is we collect a needle aspirate of the tumour, look at the cells on a slide and have the lab confirm it. If the answer is ambiguous, I’d recommend you move up to a biopsy but make it excisional, meaning instead of taking a small piece of it to identify what it is, I recommend your veterinarian remove the entire mass and then send it in for analysis since this will yield more accurate results and possibly cure the condition as soon as possible.

We also start looking to see if it has already spread somewhere else, so we perform X-rays on the chest, routine bloodwork and other blood tests to see if any organs are affected. An abdominal ultrasound could also be considered to have greater confidence that no internal lesions exist. We also often recommend a test called a puffy coat smear. This is where we take a blood sample and see if the mast cells are coursing around the bloodstream. By performing these tasks we can adequately stage the tumour before we determine the best course of action to treat it.

The tests will allow your veterinarian to build the best plan of attack to address the issue. Keep in mind that if the lesion is inflammatory in nature or is a histiocytoma, you will likely just need to perform a fine needle aspirate to confirm it and simply wait for it to resolve on its own. If it is a different kind of mass then it’s likely that greater intervention is needed.

Please watch our video “How to Address and Where to Check for Lumps and Bumps in Dogs & Cats” to get a thorough review on what to do next.

All the best and good luck.

Dr. Greenway