Skin Biopsies in Dogs and Cats

What is a Skin Biopsy?

In a skin biopsy, a small piece of skin is removed through minor skin surgery. The skin is then examined under a microscope by a veterinary pathologist to diagnose your dog or cat’s skin condition. Skin biopsies are also used to test a growth or mass for conditions such as cancer.

What Happens During My Pet’s Skin Biopsy?

The veterinarian may gently clip the fur near the skin biopsy. A sedative or anesthetic medicine may be given to make your pet more comfortable during the procedure. Different types of surgeries are performed during a biopsy. The type of surgery depends on where the biopsies are being performed and what skin conditions your veterinarian is concerned about. The most common surgeries for a skin biopsy include the following:

1. A wedge biopsy is used to surgically remove not only the skin but also the tissue under the skin (subcutis). The veterinarian angles a scalpel blade to meet as a “V” under the skin.
2. An excisional biopsy is used if your pet has a growth (skin mass). The veterinarian uses a scalpel blade to cut the growth out of the skin. Excisional biopsies are used to diagnose many skin conditions.
3. A punch biopsy is used to remove the full thickness of a small, round piece of skin. The punch tool will be placed on the area where the skin sample(s) will be taken, pressed downward to cut the skin gently, and then the piece of skin will be removed. Punch biopsies are a common way to perform skin biopsies in dogs and cats. They can also be used to obtain a skin sample for a skin culture (bacterial culture and sensitivity) to select an antibiotic for your pet’s skin infection.
4. A shave biopsy is used to surgically remove only the top layer of skin. The veterinarian uses a scalpel blade or other tool to scrape or shave off the skin. Shave biopsies are used to diagnose skin conditions that only affect the top layers of the skin.

What Can I Do to Help Prepare My Pet for a Skin Biopsy?

The veterinarian will provide you with specific instructions for preparing your pet. This may include not feeding your pet in preparation for the sedative or anesthetic medication. For the skin, do not pick at your pet’s skin or remove any crusts or scabs. The veterinarian will also tell you when to stop bathing or applying medications to the skin before the biopsy.

What Will Happen After My Pet’s Skin Biopsy?

When the procedure is over, your pet will be able to go home, and the veterinarian will provide you with specific instructions to care for your pet. Your pet may have bleeding, redness, or swelling after the biopsy. If your pet has stitches where the biopsy was performed, the veterinarian will tell you if and when the stitches need removal. If the fur was clipped for the biopsy, the fur will be shorter but will grow back.

What Happens to the Skin Sample after a Biopsy?

The skin sample is cut into thin sections and put onto glass slides. The slides then go to a laboratory for testing. A veterinary pathologist (a veterinarian trained in interpreting biopsy samples) will check the slides under a microscope to help make a diagnosis. For skin biopsies, a veterinary pathologist who has received additional training in diagnosing skin diseases called a veterinary dermatopathologist, is often used.