Lumps and bumps are something we commonly see in older dogs, and while many are harmless, a rapidly changing lump can sometimes be a cause for concern. This was the case for Marvin, who came to see us after a lump on his neck had become noticeably larger and was beginning to affect his breathing.

Marvin’s owner had also noticed significant swelling developing around the left side of his face and mouth. He had not been eating as well and was generally becoming slower, although he was still walking around at home and even finding the energy to play with the family’s new puppy.

On examination, Marvin had a large 5 × 6 cm mass on his neck, with extensive swelling affecting the left underside of his muzzle. There was no obvious separation between the two areas, making it difficult to determine whether they were part of the same process. He also had a number of other lumps, including a firm mass in his right armpit which had previously been investigated and thought to be fatty.

Given Marvin’s age, the rapid enlargement of the mass and the presence of several other lumps, one of our main concerns was that this could represent an aggressive cancer, potentially with spread to other areas of his body. Infection or significant inflammation were also considered, although there was no obvious history to suggest this.

We discussed Marvin’s quality of life with his owner, particularly his reduced appetite, slowing down and the developing breathing difficulties. Given the changes in Marvin’s appetite, mobility and breathing, we discussed the importance of closely monitoring his quality of life and ensuring he remained comfortable. His owner felt that Marvin was still enjoying life at home, so we agreed to try a short course of medication to reduce the inflammation and manage any discomfort associated with the swelling. We planned to reassess him closely over the following few days and use his response to treatment and overall quality of life to guide the next steps.

A few days later, Marvin returned – but this time the lump had burst, revealing that the enlarging lesion was a developing abscess beneath the jaw. What had initially appeared to be a rapidly growing mass had now left a deep, open wound measuring approximately 3 × 5 cm, extending down to the level of the jawbone. Despite how dramatic the wound looked, there was some good news: Marvin was now much brighter, eating and drinking better, and his owner felt that he had improved considerably since the lump had opened. Due to the extent of the wound and the amount of inflamed and unhealthy tissue present, surgery was recommended. Under general anaesthesia, the area was thoroughly flushed, devitalised tissue was removed, and the wound was carefully closed in several layers to reduce the large amount of dead space beneath the skin.

Marvin was discharged with continued antibiotics, pain relief, and a buster collar to protect the surgical site.

Marvin’s case is a great reminder that not every rapidly enlarging lump is necessarily straightforward. Although cancer remained a significant concern given his age and multiple masses, the subsequent abscessation showed how infection and inflammation can dramatically change the appearance of a lesion and cause a patient to become much more unwell.

It also highlighted the importance of looking at the patient as a whole. Despite Marvin’s concerning clinical signs, he was still enjoying time with his family and showing interest in the puppy, which helped guide the decision to give him a little more time. By closely monitoring Marvin and adapting his treatment as his condition changed, we were able to give him the chance to recover and, most importantly, find his way back to being the happy, playful dog his family knew and loved.