Lumps under cats’ skin can appear overnight or over a long period.
Abscesses from cat fights are soft and the skin is often inflamed. Once lanced and drained of pus most cat abscesses heal rapidly.
More worrisome are lumps that grow over a period of weeks or months or that are firm. Never ignore these types of bumps in a cat’s skin. Malignant skin tumours are more prevalent in cats than in dogs or other species. We should address them as quickly as possible to prevent local spread and invasion of the body.
Point out any unusual swelling or lump to your vet. A simple check of cells under the microscope will give us some idea of what it is. We may recommend biopsy or removal and send the lump to the pathology lab as a result.
The pathologist will tell us what the lump is, how benign or malignant it is and whether the surgeon has removed all of it. Often we will also find out if it is in the lymphatic system or nearby blood vessels.
Squamous cell carcinomas (skin cancer) are the most common skin tumour in the cat. They present more as ulceration of pale ears and noses than as lumps. Excision or freezing of the affected part or skin, and avoidance of the sun treats many of these cancers.
Sarcomas break all the rules however. While they remain encapsulated under the skin and rarely invade other organs, they frequently grow so large that they impede the cat’s mobility and make life very uncomfortable. Also removing all of a sarcoma is no guarantee that it won’t grow back.