Finding lumps and bumps on your pet is something which can be very scary. Skin cancer is a common problem in dogs and cats, so having your veterinarian examine your pet if lumps are found is very important.

Generally the first test that your veterinarian may run is a simple needle biopsy. This involves putting a needle into the mass and placing some cells on a microscope slide for examination. This may give us an idea of what the lump is.

A needle biopsy only samples a small area of the lump, and some masses can hide tumors inside of fatty tissue, so we often recommend surgical biopsy and histopathology for a definitive diagnosis. Surgical biopsy involves surgical removal of a small piece or the entire lump. Histopathology is when we send the sample to a veterinary pathologist who processes the tissue and evaluates it. Generally when tissues are sent off, it takes 1-2 weeks for results to return. If the mass is cancerous, the pathologist can give us an idea of how aggressive the tumor is, and if it has shown signs of spreading.

A lipoma is one of the most commonly encountered lumps seen by veterinarians during a physical exam. These soft, rounded, non-painful masses, usually present just under the skin but occasionally arising form connective tissues deep between muscles are generally benign. Most lipomas do not "have" to be removed. Occasionally, though, lipomas will continue to grow into huge fat deposits that are a discomfort to the dog and present a surgical challenge to remove. And even more rarely, some lipomas will be malignant and spread throughout the dog's body.

Not every lump or bump on your dog will be a tumor. Some superficial bumps are due simply to plugged oil glands in the skin, called sebaceous cysts. Skin cysts can be composed of dead cells or even sweat or clear fluid; these often rupture on their own, heal, and are never seen again. Others become chronically irritated or infected and should be removed. Sebaceous glands in the skin do occasionally develop into tumors called sebaceous adenomas.

So how are you to know which lumps and bumps are dangerous and which can be left alone? Truthfully, you are really only guessing without getting the pathologist involved. Keep in mind that not all lumps and bumps are cancerous, and some are fairly innocent and do not warrant immediate surgery.


Non-cancerous lumps: Cysts, warts, infected hair follicles, and others do cause concern and can create discomfort for the dog. Non-cancerous lumps, though, have less health impact than cancerous growths.

Cancerous lumps: Cancerous growths can be either malignant or benign, and occasionally even share characteristics of both. Malignant lumps tend to spread rapidly and can metastasize to other areas of the body. Benign growths tend to stay in the place of origin and do not metastasize; however they can grow to huge proportions.

Mammary gland tumors, mast cell tumors, cutaneous lymphosarcoma, malignant melanoma, fibrosarcoma and many other types of tumors with truly scary names command respect and diligent attention on the part of dog owners and veterinarians. Each type of tumor has different characteristics, and different risks.


We take a different approach to treatment of cancers in veterinary medicine than do human doctors. Chemotherapy and cancer treatment sound scary, but we use these as tools to improve your pet's life. If your pet undergoes these treatments and starts having side effects, we may modify or discontinue treatment. We want you to have a happy healthy animal for as long as possible. This doesn't always mean a cure, but we hope it means a better quality of life for our patients.


An important basic tool in eliminating a nuisance or dangerous lump is to surgically excise it. Some cancers can be cured if caught early enough just by surgical removal.


Chemicals that are highly toxic to rapidly dividing cells make up an important mode of treatment for fast growing tumors. A combination of surgery and radiation/chemotherapy can help the veterinarian gain the upper hand in achieving a cure. Chemotherapy is often employed as an additional precautionary procedure after a mass has been "removed" via surgery.


For invasive tumors that do not have well defined borders and for tumors that tend to spread rapidly, radiation therapy can be a lifesaver. Available at most veterinary medical schools and some veterinary specialists in radiology, radiation therapy is appropriate for certain types of tumors. Radiation is often employed in addition to surgical excision.


The best approach to understanding what to do about a lump or bump on your pet is to be vigilant and treat each situation individually. In cases where vigilance for tumors is part of the animal's care, such as in animals where a malignant tumor has been removed and the veterinarian wishes to keep abreast of the stage of disease, then EVERY lump should be submitted for histopathology. In other cases where the clinician is sure of a benign diagnosis such as sebaceous cysts or a wart-like skin mass then it might be understandable to use discretion. The clinician also has to take into consideration the risk of surgery compared to the risk of health problems from a particular lump or bump.

Take a good surface inventory of your pet today, then at least once a month from now on. If you find any imperfections, take heart in knowing that modern veterinary medicine has some very effective remedies for almost all of these lumps and bumps.


Veterinary Partner:Lipomas in Dogs and Cats

Veterinary Partner: Sebaceous Adenomas

Pet Health Network: Sebaceous Cysts

Veterinary Partner: Mast Cell Tumors

Veterinary Partner: Lymphoma in Dogs, Lymphoma in Cats

Oncology Referral for your Pet: What to Expect