Help! My dog’s got a lump!

First, don’t panic. Second, get it checked.

There are many parts of the body a dog (or cat) can develop noticeable lumps, including skin, eyelids, inside the mouth, even on the anus, and the lymph nodes (glands). Today we’ll have a look at some of the common skin lumps of dogs.

Many of the lumps are totally benign. These include sebaceous cysts (overgrown blocked pore), warts (particularly common in ageing terriers, spaniels, poodles, bichon frisés), and foreign bodies (especially now, in the bone-dry summer – grass seeds and other prickly plant bits pierce the skin and set up inflame, infected swellings).

You will probably have heard of fatty lumps – lipomas. These grow under the skin, making a smooth swelling. They can be as small as a boiled sweet, and as big as a melon. They can occur in any breed of dog, but the really big ones seems to prefer labradors and springer spaniels. They grow irrespective of how overweight the dog may be. Made of fat, they are harmless. They can, however, impede the dog’s mobility if they decide to grow, particularly in the armpit or groin. The dog ends up having to swing its leg to get around the lump. I recently removed one that weighed 1kg!! It was revolutionary for the dog, who had been waddling and whose knees were aching badly from the strain (see picture).

Whether or not your dog’s lipoma needs removing would depend on location on the body and how fast it was growing. Some of them sit there without changing for years. Others grow steadily from the beginning – thesis are the ones where surgery is more indicated.

The majority of lumps that FEEL like they will be lipomas ARE lipomas. However, some are a very different proposition. The key is getting a diagnosis; after that, you can relax. A needle sample (fine needle aspirate, FNA) will quickly determine, in the consultation, if the lump is just made of fat. Needle samples, performed correctly, will give a representative answer 80% of the time. The 20% failure rate comes when the lump may be infected or inflamed, and only pus cells are collected by the needle. Or, the lump may be a type that doesn’t give up its cells readily. However, these kind of lumps are often suspected based on their appearance.

One common tumour that does yield good samples is the mast cell tumour. These can be extremely variable in appearance and behaviour. They can grow on the skin, possibly as a red itchy lump similar to a human mosquito bite. They can also grown under the skin, mimicking a fatty lump to the touch. Mast cell tumours are to be treated with respect. They give off histamine (normally released in allergic reactions) and are cancerous. (Picture below shows a cancerous mast cell (circled) and histamine granules (arrow)).

Having said that, approximately 90% of them are curable if the correct type of surgery is used. Understanding what it is and how it is behaving, maximises success – the traditional saying in these situations is “the first cut is the cleanest”. We want to only remove the minimum area necessary, but taking ENOUGH tissue is imperative to prevent regrowth from the microscopic cells that may be spreading in the area. You can see, therefore, that blindly snipping off a lump, without attempting to find out what it is first, could result in potentially unnecessary further operations, or, worse, spreading the disease in your dog.

One of the exceptions to the rule of “test first” are eyelid lumps. Nearly all lumps that grow on dog eyelids will be based on a wart or a blocked eyelid-lubricating-gland. These are both benign and obvious from appearance.

As a mood-lightener to what has been a fairly serious article – do put your specs on if you think your dog has a tick….. Over the years, I have encountered several clients who have breezed into the consulting room announcing that “the dog has a tick but keeps biting me when I try to remove it”. All bar one of these has resulted in discovering the client has been trying to twist and pull off a wart or nipple. I, too, would bite.