A common question I am asked is about lumps that pet owners have found on their pets. These can be lumps on the surface of the skin or under the skin. In general, lumps that have come up suddenly, are growing quickly (e.g. have doubled in size in one month or less), are oozing, are an odd colour or are bothering the dog or cat should be checked by a veterinarian.
You cannot tell just by looking at it if a lump is cancerous or not. Typically I recommend either a fine needle aspirate or biopsy to try to determine what type of lump it is. A fine needle aspirate involves putting a needle into the lump and aspirating cells out of it. The cells are transferred to a slide and sent to the lab for a pathologist to review. It is not always possible to get a diagnosis with a fine needle aspirate and then a biopsy is recommended. Some lumps do not exfoliate cells well, and the pathologist doesn’t have enough cells to make an accurate diagnosis. In some cases, if the lump is small, we will remove it and then send the entire lump for biopsy. If the lump is larger than a biopsy can be taken with a local anaesthetic (sometimes sedation is required as well) to obtain a small piece of tissue for the pathologist to examine. Then, based on these results, we can usually determine if this lump is cancerous or not. If the lump is not cancerous and not causing problems (not oozing, the dog or cat is not chewing at it), then it can be monitored. If the lump is cancerous, then a plan for surgery or treatment can be made. If a lump is cancerous and is aggressive (e.g., may have metastasized or spread to other parts of the body), then staging is recommended. Staging may involve aspiration of lymph nodes, chest x-rays, abdominal ultrasound, bone marrow aspirate, etc. If there are signs that cancer has spread to other parts of the body, then chemotherapy may be recommended as well as surgery.
If your pet has a lump that you are concerned about, please make an appointment to have your veterinarian examine it as soon as possible.
Written by Lori Skrypnek, DVM