Finding a growth on your pet can be an uneasy experience. Growths can range greatly in size, shape, and colour, and their significance can also depend on where they are located on the body. Noting the rate of growth of a nodule or mass is also important. In any case, a full physical examination and cellular analysis of the lump is necessary to determine whether or not it poses a threat to your pet’s health. Common lumps include benign fatty tumours (lipomas) found in older pets, but these must be differentiated from cancerous growths.
The first thing to do upon finding a lump is to note where it is located, as well as its size and appearance. Your Veterinarian will have the tools to accurately measure the size of the lump, so that in the future it can be objectively compared to determine whether or not it is growing. The texture, location within the layers of skin, and appearance should be recorded and taken into consideration. Your pet should be checked over head to toe for other growths, and the details with respect to the findings should be noted as well.
Your Veterinarian will likely recommend testing of the lump to determine what it is. The most common test is a fine needle aspirate (FNA), where a needle will be passed into the lump and cells drawn out by the suction of a syringe. The cells are placed on a slide and are analyzed to determine the cellular composition of the growth. As well, the characteristics of the cells may give an indication whether or not it is likely benign or malignant. The benefits of this test are that it is a minimally invasive test, it rarely requires sedation, and for most growths it can lead to an accurate diagnosis. The limitations of a fine needle aspirate often are a result of the small sample size that can be obtained. Occasionally, a truly representative sample population of cells cannot be obtained using this method. In this case, the next step would be a biopsy.
A tissue biopsy is the most accurate way of determining what a lump is, including whether or not it has significant health consequences for your pet. The sample is analysed by histopathology, where a cross-section of the sample is interpreted by a histopathologist. The benefit of this test is that a larger and more representative sample can be obtained, and the cells and tissue structures can be seen in relation to eachother. Often a prognosis can be provided with the diagnosis. A tissue biopsy requires sedation and often general anesthesia, as the pet needs to be absolutely still and the procedure can be painful if performed on an awake patient.
Visiting your Veterinarian as soon as a growth is found is the best preventative medicine for your pet. The sooner a nodule or mass of concern is tested and removed, the better the chances of a good outcome for your pet.
Written by Dr Beverly Wong, DVM
Markham Veterinary Clinic