To make it easier to find the lump in the consult, Charlotte had marked it with a marker so that we could easily find it again. The lump was slightly raised from the skin and approximately 1cm in size. it was recommended to sample the lump, which we did by putting a needle into the lump and sucking out some cells. This is a non-invasive and fairly non-painful way to try and get an answer as to what the lump was.
Unfortunately, the sample came back as Poppy having a mast cell tumour, which is one of the more common types of skin tumours we see in dogs. Mast cells are one of your allergy cells and produce histamine, the chemical associated with allergic reactions. These types of lumps can often go up and down in size as the cells release histamine, causing an inflammatory response within the lump and surrounding tissue. Then they get a bit smaller, sometimes giving owners the false hope that the lump is going away on its own.
One major issue with mast cell tumours is that they can range from low to high grade and we can’t grade them with just a needle sample, we need to take a biopsy to be able to see how aggressive the tumour is. High-grade tumours are associated with a median survival time of only 4 months as they have often spread before the diagnosis is made. Low-grade tumours are associated with a greater than 2-year survival and in most cases surgically removing the tumour is curative so long as all the cancerous tissue is removed.
Poppy had surgery to have the lump removed with a large margin of healthy tissue around it to ensure all the cancerous cells were removed. The great news is when the pathologists analysed the tissue sample they found it to be of low grade with a good margin of cancer cell free tissue around the lump, meaning we removed the whole tumour. Poppy's owners will still need to monitor the site but the prognosis is very good.
This shows that even a small lump should get checked by your vet. If it is in a hard to find spot, or is quite small, marking it with a marker so we can find it again as Charlotte did to Poppy's lump makes it a lot easier and saves another visit if we can't find the lump in the consulting room. Most diagnoses can be made by taking a needle sample, with about 5% need a tissue biopsy to diagnose what type of lump we are dealing with to be able to then recommend the best treatment options for your pet.
Dr Nikki Frost BSc BVSc MANZCVS (Medicine of Cats)