Finding a lump on your dog is quite common, especially as they age.
Skin and subcutaneous (beneath the skin) tumors are the most common tumor to affect dogs.
The good news is the majority of these tumors are benign.
In this column, I’ll describe the plan that most veterinarian follow when presented with a pet that has a lump. Finally, I’ll describe a few common tumor types.
Unfortunately, it is not possible for your veterinarian to diagnosis a skin tumor as benign or malignant just by looking at it. In some cases the appearance and texture may give clues as to the type of tumor, but tests are still necessary. The first step in analysis of any lump will likely be a test called a Fine Needle Aspirate (FNA).
The FNA can be quickly and easily performed during the office call.
A small needle is passed into the lump to remove a microscopic sample of cells which are then transferred to a microscope slide and reviewed. The results of this test allow the veterinarian to decide if the lump is more likely to be benign or malignant based on the appearance of the cells obtained.
An FNA has the advantage of gaining important information without being invasive or using anesthesia. The test is also relatively inexpensive.
However, results can be equivocal. This test will not identify the exact tumor type in many cases and a misdiagnosis is possible if the needle misses cancer cells during the aspiration procedure.
If the results of the FNA reveal benign appearing cells, your veterinarian will likely tell you to monitor the lump for changes. However if the results reveal cells suspicious for cancer, the second step in analysis of the lump will likely be a biopsy.
The biopsy procedure involves excision of the entire lump or a section of it. This test will most likely yield a definitive diagnosis. However, this test will require heavy sedation or general anesthesia and will be more costly.