Biopsy in Dogs

Biopsy is a surgical procedure used in dogs to obtain a tissue sample for diagnosis of a variety of pathologies, from cancer to skin disease. The goal of biopsy is to provide a veterinary pathologist an accurate picture of the disease process taking place so that they may report the suspected disease or type and stage of cancer in your dog. Biopsy is a common procedure often used to diagnose dermatological issues and certain cancers. Your veterinarian will perform the biopsy (or refer to a veterinary surgeon for more involved biopsy) and then submit the tissue sample obtained from biopsy to a veterinary pathologist for interpretation. 

The biopsy procedure will depend on the type of biopsy selected for your pet. In general, your dog will be placed under anesthesia for the biopsy procedure. The tissue sample will be taken and submitted to a veterinary pathologist for interpretation. Your dog will likely need stitches after receiving a biopsy. Below are some examples of what to expect from different kinds of biopsies.

Punch Biopsy

This biopsy method is most commonly used to diagnose dermatological conditions. Local anesthetic or general anesthetic may be used depending on the nature of the biopsy. For the procedure, the skin to be biopsied is cleaned and shaven. A small tool is used to bore into the skin penetrating all layers of the dermis the tool is removed taking a cylindrical piece of tissue with it. The tissue is placed into a solution to preserve it and sent for histopathology reading. The wound left by the punch biopsy is sutured closed with 1-2 sutures. 

Jamshidi Needle Biopsy

This biopsy method is used to diagnose bone cancers. General anesthetic is used to ensure that the patient will remain completely still throughout the procedure. The skin over the area to be biopsied is shaved and sterilized. The bone biopsy needle is then bored into the bone through the suspect lesion ensuring that the needle passes all the way to the middle of the bone. The small pieces of bone obtained are placed in solution and sent for histopathology. 

Tru-Cut Biopsy

This biopsy method is a less invasive way of obtaining certain tissue samples. For this biopsy, the animal is placed under general anesthesia and the area over the tissue to be sampled is shaved and cleaned. The tru cut device is placed over the tissue to be sampled and either guided by ultrasound (for internal organs such as the kidney) or placed directly in the tissue (for muscle biopsy). After the tru cut biopsy is performed tissue is sent for histopathology. No sutures are needed after this kind of biopsy. 

Surgical Biopsy

The biopsy methods listed above are considered incisional, meaning that some of the affected tissue or cancer is left behind. Excisional biopsy, such as surgical biopsy aims to extract all affected tissue for examination. This is especially important for cancer treatment. Radical excisional biopsy requires general anesthesia and is a much more invasive procedure. For this type of biopsy, the cancerous lesion is removed along with a margin of healthy tissue to ensure that the cancer does not return. This procedure is done under general anesthesia and requires stitches. The tissue obtained from this procedure is then sent to histopathology where a veterinary pathologist determines if margins attempted in surgery were wide enough or if more surgery is needed to extract all of the cancerous tissue.

Biopsy is an effective tool for the diagnosis and/or staging of cancer and other pathological conditions. Because more tissue is included in a biopsy sample for histopathology a veterinary pathologist will have an easier time understanding your dog’s diagnosis in the context of the tissue it is affecting. For other diagnostic measures such as skin scraping or fine needle aspirate, only some cells are removed so the full extent of disease cannot be understood. However, these other techniques are much less invasive than biopsy and do not require suture or anesthesia. 

Recovery from biopsy depends on the method of biopsy used. For less invasive procedures, such as punch biopsy, recovery generally involves the recovery from anesthesia. However, for radical excisional biopsy, such as when a leg is amputated due to bone cancer, recovery will be much more intensive and require physical therapy and a pain management protocol for your dog. In general, recovery from biopsy will involve taking precautions for sutures, i.e. making sure that your dog remains still for 10 days while sutures heal and monitoring the recovery site for any signs of infection such as redness, swelling, or discharge. Recovery from biopsy may also involve pain management, which can range from oral pain pills for a few days to a fentanyl patch for more constant dosing of pain medication. 

The cost of biopsy varies between the different kinds of biopsies used. Less invasive biopsies such as punch biopsy will cost between $400-$800 while more invasive or more involved surgeries could cost up to $2,500 (including hospitalization and medications). 

As with any surgical procedure, there are risks associated with biopsy. Your veterinarian will do bloodwork to ensure that your dog is healthy enough to receive anesthesia as needed for the procedure. Other risks associated with biopsy include bleeding, pain and infection. Biopsy is an excellent tool to create a clear clinical picture in cases of cancer, skin disease and kidney and liver disease. For bone cancer, biopsy is 90% effective at providing an accurate diagnosis. As certain kinds of biopsy are also considered treatment, such as radical excisional biopsy, it can be worked into a therapeutic plan and combined with other treatment such as radiation oncology and chemotherapy. 

Preventing biopsy means prevention the conditions that require biopsy. Preventing cancer is unfortunately very difficult to do. It is difficult to pinpoint exactly which external and internal factors play a role in cancer development in dogs. Some dogs are predisposed to developing certain cancers based on their breed. Many dogs develop cancer as they advance in age. Though preventing cancer is difficult, there are certain cancers that can be prevented with surgery. For example, mammary tumors, common to female dogs, can be prevented by spaying your dog before her first heat cycle. Testicular tumors can be prevented by getting your dog neutered. 

Keeping your dog in good health in general will help if cancer is suspected as they will be better candidates for surgery, chemotherapy and all other necessary treatments. Taking your dog in for regular veterinary visits throughout their life will achieve the goal of keeping them in good health and will help ensure that if cancer does form, it is discovered early.

 Keeping your dog in good health can also help prevent kidney and liver disease that may need biopsy to differentiate them from certain cancers. Preventing the skin conditions that require biopsy may prove difficult as well, as they are largely heritable. If possible, understanding your dog’s lineage could go a long way into understanding the heritable conditions that may affect them in the future. While this knowledge will not prevent a heritable condition from arising, it can help provide insight about what is going on and help your vet make appropriate treatment and diagnostic decisions.