A biopsy involves studying tissue taken from a living body to detect, determine the cause, or gauge the severity of a disease. If your rabbit has a lump, lesion, or any tissue irregularity, your vet might suggest a biopsy to help diagnose the issue and decide on a treatment strategy.

Taking a lung biopsy ©Stephen Hernandez-Divers & Maud Lafortune

A biopsy, recommended by your veterinarian, can serve multiple purposes. It can help evaluate lesions or lumps to determine if cancer is present, or to determine what treatment may be necessary. Biopsies can be taken from most organs including the skin, liver, or kidneys and can be indicated if the veterinarian finds a lesion or lump on the physical exam, or as a result of other diagnostic findings that indicate a liver problem. Biopsies can be combined with other diagnostic methods like blood tests, ultrasounds, or x-rays, to explore the full extent of a problem, and to determine a cause for the disease.

Most areas of a rabbit can be biopsied. Some biopsies are easier to perform than others and some carry significant risks of complications. Areas that are commonly biopsied include:

• Skin biopsy: these can be a valuable tool when investigating dermatologic (skin) disorders; helping to provide a definitive diagnosis in a variety of skin conditions, so that correct treatment can be offered.
• Liver biopsy: these may be indicated if the vet has found evidence on the physical exam such as jaundice, or an enlarged liver, it may also be indicated if the blood tests have shown raised liver enzymes, or if a radiograph or ultrasound shows liver enlargement or an unexplained lump in the liver. Using a liver biopsy to confirm a diagnosis and offer the appropriate treatment and prognosis is invaluable. Treatments for a diagnosed liver issue vary depending on the issue but may include liver support medications, antibiotics, chemotherapy, or surgery.
• Kidney (renal) biopsy: renal biopsies are indicated in cases of suspected renal dysfunction in which the underlying cause cannot be determined by less invasive methods, ie ultrasound, blood tests, etc. Renal biopsies carry significant risks so are avoided unless there is clear benefit to improve the pet’s quality of life.
• Lung, chest wall or mediastinum biopsy: if there is a mass within a lung, on the chest wall or in the mediastinum, a biopsy of this will assist with a diagnosis. These biopsies can carry significant risks so are avoided unless there is clear benefit to improve the pet’s quality of life.
• Lymph node biopsy: lymph node biopsies in rabbits are usually performed to diagnose or assess the extent of diseases or abnormalities, like unusual or persistent enlargement of the lymph node. These biopsies are reasonably straightforward and are useful if diagnosing infection, inflammatory conditions, and cancer.
• Intestinal biopsy: the intestine is a common site for various disorders in rabbits. Biopsy of the intestine can provide valuable information for the diagnosis and treatment of many disorders including enteritis, malabsorption, parasites, and cancer.

There are several different types of biopsies that can be taken:

• Needle biopsy: this will often be the type of biopsy performed when internal organ biopsies are required, such as liver, kidney, lung, or intestine is taken. The use of ultrasound to guide the veterinarian into the correct area is frequently used to help locate the exact internal location of the biopsy area. When the biopsy is performed, suction (from a syringe) is used to draw cells and tissue back into the needle, so they can be drawn out of the body and extracted onto a microscope slide that can be sent and analyzed by the laboratory.
• Wedge biopsy: these are when a section of the tissue is cut away with a scalpel blade, usually from skin lesions. Afterwards, one of two sutures may be used to close the skin.
• Punch biopsy: punch biopsies use a specific tool that is pressed into the tissue, creating a circular plug of tissue that can be pulled out and cut off. These plugs of tissue are placed in preservative solution and sent to the laboratory for analysis. Again, sutures are usually used to close the circular hole that is left after the plug is taken.
• Endoscopic biopsies: endoscopic biopsies are one of the safest ways to take a biopsy of an internal organ like the liver, kidney, lung, or intestine. The endoscope is an instrument with a long thin tube with a camera on the end. The end is inserted through a small skin incision to enter the body cavity and when it is at the biopsy site, small tools can be extended out of the tube to collect the tissue biopsy. The tube grasps the tissue and is drawn out of the body where the sample is collected and placed into a sample jar so that it can be sent to the laboratory for analysis. Sutures are placed to close the small wounds created by the endoscope. Endoscopy is traditionally safer than traditional surgery as it is faster and minimally invasive, so healing and recovery time is much faster. If an endoscope is not available at your veterinary practice, your veterinarian might refer you to another practice if an endoscopic biopsy is needed for your rabbit.

It may be possible to obtain small, skin biopsies and lymph node biopsies from your rabbit using systemic pain relief and a local anesthetic in the skin, but this will depend upon the location of the lump, the size biopsy required, and the temperament of your rabbit. Most of the time sedation or general anesthetic will be required for all biopsies regardless of the site. This is because the rabbit will need to stay perfectly still, and as a sample of skin/tissue is being taken, this will be unconformable for the rabbit.

For most biopsies that require sedation or anesthetic, your rabbit will be admitted to the veterinary practice for the day. It is important you do not withhold food or water from your rabbit prior to the procedure, unless otherwise instructed by your veterinarian. When you drop off your rabbit, take in some of their food, and their companion, to help to relieve stress. Before the procedure, the sedation or anesthetic will be administered. Typically, an area of fur will be clipped away to enable the skin to be cleaned and the area to remain sterile during the procedure. This is important to prevent infection and promote fast wound healing. The biopsy will be surgically performed, and some sutures (stitches) may be placed to close the skin afterwards. Once your rabbit is awake from their sedation or anesthetic, and has eaten, your veterinarian will call you to collect them. If there are sutures that need to be removed when the wound is healed, your veterinarian will explain this to you and book you a follow-up appointment.

With any sedation of anesthetic there is always a risk involved as your rabbit may not tolerate the drugs well, these risks may increase if your rabbit is already compromised by a disease process. Added to this, biopsies of the liver and kidneys have some risk of hemorrhage during or after the biopsy. Biopsy sites can break down during the recovery period, which is especially true with intestinal biopsies. These can be extremely serious and lead to peritonitis and can potentially be fatal. Your veterinarian will consider all risks and take all reasonable steps to minimize negative outcomes from the procedure.

As your rabbit will be sedated or have a general anesthetic, they will not feel the biopsy being taken. Pain medication will be given so that your rabbit feels minimal discomfort when it wakes up from the procedure. If your rabbit is likely to be uncomfortable after the procedure, your veterinarian will prescribe pain medication for you to continue with at home in the days afterwards.

It may be that your veterinary practice has an on-site laboratory and pathologist who can analyze the biopsy sample and report the results within a few hours or days. More often though, samples are sent to an external laboratory, and it can take a week or more for the results to be sent to your veterinarian, who will then contact you to discuss the findings and what they mean.