DIAGNOSING SKIN TUMORS IN YOUR PET
The most common location for a dog to develop a mass is on the skin or underneath the skin surface. These types of masses may not be as common in the cat, but can still occur. Most of the time, these masses are found while you are petting or playing with your pet at home. Sometimes, masses can be found by the family veterinarian at annual wellness visits. Annual visits to the veterinarian are important for many reasons as your pet ages. Locating and diagnosing new masses is just one example of the importance for these wellness visits.
There are a variety of tumor types that occur on the skin or underneath the skin. Your veterinarian may be able to narrow down the possible tumor types based on appearance, however, the best way to definitively figure out the origin of a mass is to perform a fine needle aspirate or a biopsy. There are exceptions to this recommendation in cases where pets have small warts or skin tags. Those may appear like small masses on the skin and they may not be able to be aspirated or biopsied due to their small size.
A fine needle aspirate is a non-invasive test to determine the origin of a mass. A small needle (about the same size that would be used to draw blood) is inserted into the mass. Some cells from the mass will enter the needle when it is inserted into the mass. These cells are then spread onto a glass slide for evaluation. Sometimes your veterinarian may be able to evaluate the cells under the microscope, but there are times when the slides are sent to a pathologist for review.
On some occasions, your veterinarian and a pathologist may be unable to determine the origin of a mass based on fine needle aspirate alone. Some tumor types, both benign and malignant, will not release their cells very easily and can be difficult to diagnose with a fine needle aspirate. At this point, a biopsy may be necessary. For a biopsy, your pet may need to be sedated or placed under general anesthesia in order for a small piece of tissue to be obtained. Alternatively, a biopsy may be able to be performed with just a local anesthetic. Once the tissue sample is obtained, it is placed in formaldehyde and sent to a pathologist for review. A biopsy may provide more useful information to your veterinarian or veterinary oncologist than a fine needle aspirate. Since more tissue is available for review, different parameters such as tumor subtype, grade, and how fast it is growing can be determined from the biopsy. These are important parameters to determine how aggressive the tumor is behaving and what your pet’s prognosis is with or without treatment.
If you are concerned about a mass present on your pet, please contact your veterinarian for evaluation. A veterinary oncologist may be contacted to discuss treatment options if your pet is diagnosed with a malignant tumor.
Karri Miller DVM, MS, DACVM (Oncology)
Lap of Love Veterinary Hospice
Dr. Karri Miller provides Skype and Phone consultations to families across the United States whose pets have been diagnosed with cancer. As a Board Certified Oncologist, she will be able to provide your family with information about cancer, treatment options, and expectations.
Blog originally prepared for the Lakeland Ledger (Florida)
Posted by Vet Mary Gardner