Mimi is a very sweet little greyhound who came to visit me when her owner noticed a sudden change to a lump. There had been a small, soft lump on Mimi’s left shoulder for a long time – months, possibly years – but it had remained small and unchanged. Over the course of a few weeks, however, the lump had noticeably grown and, whilst this wasn’t bothering Mimi, it was understandably worrying her owner.

During the initial consultation we discussed the lump and examined it, but we agreed that we needed to gather a bit more information by taking a sample. In most cases we start the sampling process with a ‘fine needle aspirate’(FNA), which involves placing a small needle into a lump with the aim of collecting some of the cells that it is made up of. This is usually done while the animal is conscious, unless they are needle-shy or the location of the lump makes this unsafe. The cells are then transferred onto a microscope slide and analysed by trained cytologists at our external laboratory.

The outcome of results can vary depending on how easily the cells within the lump exfoliate (shed). Sometimes the cytologists can identify an exact cell type and give us a definitive diagnosis for the lump. At other times, the sample is not clear enough and they need a larger piece of tissue to assess. Occasionally, as in Mimi’s case, the result sits somewhere in the middle: they could identify that the lump was a ‘soft tissue sarcoma’ – a type of cancer – but they could not clearly determine whether it was low or high grade.

Grading these types of tumours is essential for decision-making because they are locally invasive and can spread into surrounding tissues. A low-grade tumour typically requires a less extensive surgery, whereas a high-grade tumour often requires much more aggressive removal. In Mimi’s case, that could have meant amputating her front leg, which we were keen to avoid unless absolutely necessary.

Mimi’s initial results were a useful first step in the diagnostic process, but we still needed more information to plan the best treatment. She therefore came back to see me for a general anaesthetic so that we could take X-rays of her chest to look for any tumours in her lungs (thankfully, these were clear) and take a larger piece of the lump via a ‘surgical incisional biopsy’. This allowed the laboratory team to analyse the tissue in more detail, although it meant we had a further wait for results.

Approximately a week later, the biopsy results came back and indicated that the mass was most consistent with a low-grade soft tissue sarcoma. This meant we could attempt surgical removal without needing to amputate her leg.

The recommended approach for removing low-grade soft tissue sarcomas involves excising the lump with 2–3 cm of clear, normal tissue around it, as well as a layer of normal tissue beneath it, to maximise our chances of removing all cancerous cells that may have spread into surrounding tissues. Mimi’s lump itself was only about 1.5 cm in diameter, but once we added the recommended margins, we were faced with a very large area of skin, connective tissue and muscle to remove. This would leave a substantial defect to close, with very little spare skin – particularly challenging given that Mimi is a greyhound and the lump was located on her shoulder.

Thankfully, Martin was on hand to lend his expertise and help me plan an extensive skin flap. A skin flap involves making an incision into healthy skin close to the surgical site and then carefully rotating this tissue to cover the area where the lump has been removed. Mimi started the day with a 1.5 cm lump on her shoulder and ended it with hundreds of stitches running from her elbow, around her shoulder and across her left side. It was a drastic procedure, but a necessary one.

The following few days were challenging post-operatively. Although Mimi was a complete angel throughout the entire process, she temporarily had some difficulty moving around. Unfortunately, one week later, a small area of the skin flap broke down. However, the majority of it remained intact, and with the expertise and care of nurses Hayley and Daisy, Mimi received a series of dressings to support the surgical wound, keep it clean and healthy, and allow it to heal. It truly was a whole team effort – including the excellent care and attention Mimi received at home from her owners.

Each week it was wonderful to see how much better she looked and how well the wound was healing. To top it all off, the final analysis of the lump confirmed that we had successfully removed all the cancerous cells. Whilst this was the best possible news and made everything feel worthwhile, regrowth of soft tissue sarcomas is common, so we will be keeping a very close eye on Mimi moving forward.

The key messages from Mimi’s story are that lumps are important, especially if they appear suddenly or change in size or character. We should monitor lumps closely, but ideally sample them early to understand what they are and determine the most appropriate course of action.