Pet Factsheets


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Your pet may undergo a biopsy to determine if a growth is cancerous or noncancerous (benign). The tissue removed during a biopsy is examined under a microscope by a veterinary pathologist, a specialist in examining cells and tissue samples.

What is a biopsy?

A biopsy is a surgical procedure in which a tissue sample is removed from the body and examined under a microscope. In some cases, only a small sample is removed for analysis - in other cases, several samples may be removed, or an entire growth may be removed and examined.

Why does my pet need a biopsy?

Dogs and cats commonly develop lumps and growths on their skin. Sometimes these are cancerous, but they can be warts or other noncancerous (benign) growths. Your veterinarian may not tell from examining a lump whether it is cancerous or not, so may recommend a biopsy to obtain more information about a suspicious lump.

A biopsy can also be used to diagnose a condition or determine the severity of a disease. If a pet has liver disease, a sample of the liver can be removed by biopsy and examined under a microscope to help determine the cause and extent of the liver damage.

What happens during a biopsy?

Your pet will generally require some form of anesthesia for a biopsy. Your veterinarian will decide whether to use local anesthesia, sedation, or general anesthesia depending on where the tissue sample is located and how many areas need to be sampled.

Local anesthesia involves injecting a medication in and around an area of the body to make it numb. With local anesthesia, your pet will likely be awake during the biopsy. If sedation or general anesthesia is used, the patient is heavily sedated or completely asleep during the biopsy. If a growth is on the surface of the skin and is very small, the biopsy may be carried out using local anesthesia, but if the area to be biopsied is within the abdomen, or if multiple areas will be biopsied, general anesthesia is usually recommended.

In an incisional biopsy, a small sample of tissue is removed from a larger mass. In an excisional biopsy, the entire growth is removed and submitted for biopsy.

Once the tissue is removed, the sample will be examined at a diagnostic laboratory where a veterinary pathologist will examine the tissue under a microscope to make a diagnosis. Results are generally available within several days.

Are there any risks?

Biopsies are very important for helping to confirm a diagnosis. Early diagnosis is helpful for determining the course of treatment with many types of cancer and can help increase the chance of survival. Biopsies can also help to confirm causes of other conditions, including skin lesions as well as diseases of the kidneys, liver, or bone marrow.

Your veterinarian will take precautions to ensure that your pet is safe during the biopsy and recovers fully afterward. To help reduce the risk of complications associated with surgery or anesthesia, your veterinarian may give your pet a full physical examination and take blood samples before the biopsy.

Biopsies are very safe, routine procedures. Any risks associated with a biopsy depend on the overall health of the pet, the location of the area to be biopsied, and how many samples are taken. Your vet will be happy to discuss any concerns that you may have.

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