VET SPEAK: Alison Laurie-Chalmers of Crown Vets in Inverness talks about the importance of checking any lumps
Punch was a bouncy, exuberant, four-year-old boxer dog. He was brought into the practice as the owners had noticed the sudden appearance of a red, raised, round, lump on one of his front legs.
Punch was not bothered by his lump, he gave it an occasional lick, otherwise he left it alone. It was a lump that had not been noticed before though, and his owners were understandably concerned.
I advised that this lump was sampled initially using a fine needle biopsy, and the sample was sent to the laboratory. The result came back as a confirmed cutaneous histiocytoma.
A cutaneous histiocytoma in a dog is a common, benign tumour composed of histiocytes. A histiocyte is a cell that is part of the body’s immune surveillance system. Histiocytes take up and process foreign antigens, such as pollens and viral, bacterial, and fungal micro-organisms. They then migrate to the local lymph nodes. Here they present antigens to other immune system cells to stimulate them into a variety of activities to protect the body.
In their early stages, over the first couple of weeks, histiocytoma lesions can grow quite rapidly. During this period they can ulcerate and be self-traumatised, and may then become secondarily infected. Histiocytomas may then quietly regress and disappear spontaneously over a period of a few weeks. This spontaneous regression is common in these tumours.
This tumour can occur in any dog, but some breeds appear more susceptible, including bulldogs, American pit bull terriers, American Staffordshire terriers, Scottish terriers, greyhounds, boxers and Boston terriers.
Most commonly, histiocytomas are found in young dogs, although they can occasionally be found in older dogs. Most dogs affected though are less than six years old, occasionally as young as eight weeks. They appear as a small, round, solitary, hairless, inflamed lump. They are mostly found on the head, neck, ears and lower limbs, and are usually less than 2.5cm in diameter.
An accurate diagnosis relies on tests. Depending on the presentation and location of the lump, your vet may recommend one or more methods of obtaining a tissue sample for a full diagnosis. It is important to sample these lumps as they can look and present similarly to other much more concerning cancerous tumours.
The lump is sampled using a small needle to take some cells. These cells are analysed under a microscope to identify their origin and any indications of any malignancy.
Sometimes however, it is not always possible to achieve a definitive diagnosis in this way, in which case your vet will recommend removing a larger biopsy sample or removing the whole lump.
This is one of the rare types of tumours that the body’s own immune system can eventually eliminate. However, lump growth in size, change in structure, ulceration, itching, secondary infection and bleeding are often problems that then require surgery.
Thankfully, Punch’s lump visibly regressed quickly and resolved spontaneously over a few weeks and so did not require surgery. He was then carefully monitored regularly every few months at the practice for any recurrence, and for any other bumps and lumps.
Contact your vet if you are concerned about any lumps on your dog’s skin. Not all lumps in dogs are cancerous but having them examined and tested is the safest way to monitor any lesions, and for the good and long-term health of your beloved pet.
Alison Laurie-Chalmers is a senior consultant with Crown Vets in Inverness.
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