Types of Canine Cancer Tumors

There are many types of canine cancer. Generally, you should monitor your pet for lumps, bumps, skin discoloration or swelling. Each of these common symptoms can be present in different diseases and conditions, as well as a number of cancers.

Monitor behavioral changes in your dog. Cancerous dogs do tend to become lethargic. You might find blood in their stool or urine, depending on the form of cancer. Breathing difficulties may occur if a tumor is in or near the lungs. Vomiting and nausea may lead to weight loss because the dog simply isn't hungry.

Hemangiosarcoma Canine Cancer

Hemangiosarcoma is extremely aggressive and usually fatal. The cancer develops in the blood vessels and spreads rapidly to other areas, particularly the heart, liver, skin and spleen. Hemangiosarcoma that presents on the skin does offer a better prognosis than other forms.

If the cancer spreads to the abdomen, it's usually easy to feel large lumps and masses. The tumors will be surgically removed and chemotherapy is used to extend the dog's life. For the skin form, look for discolorations or small lumps. Surgical removal of the skin tumors and chemotherapy will be advised.

Histiocytoma Canine Cancer

Histiocytoma is most common in dogs younger than three. The tumors appear as round bumps, most commonly located on the head or face. The tumors shrink over time and disappear completely. Watch the tumors to see if they become inflamed or infected, especially if the dog scratches at it, and visit a vet if they do seem to swell or look infected. Otherwise, it's usually best to leave them alone.


Lymphoma is a form of cancer that affects the lymph nodes and organs. It's important to catch the canine cancer as early as possible, because chemotherapy works well at killing tumors.

Symptoms depend on the location of the lymphoma. Swollen lymph nodes may occur. If the tumors occur in the stomach, your dog may vomit, lose weight and have diarrhea. Chest tumors lead to breathing difficulties and a muffled heart beat. Skin tumors may resemble an itchy rash on the skin or in the mouth.

Mammary and Testicular Canine Cancers

Dogs that are not fixed have a higher risk for developing mammary or testicular cancers. Female dogs develop tumors in their mammary glands that feel like small stones. Having your female dog spayed before her second year greatly reduces the risk of mammary cancer.

Testicular cancer is only possible if your dog is still intact. Dogs that undergo vasectomies rather than a full neutering are at risk for testicular cancer. Swollen testicles or scrotum are a key sign that tumors are present.

Mast Cell Tumors

This is an extremely common form of cancer in dogs. Check your dog's skin regularly to look for bumps. They may be smooth or bumpy and may form open ulcers. You'll usually see them near the genitals, legs and trunk.

Osteosarcoma Canine Cancer

This is a less common bone cancer that is generally seen only in large breeds like Great Danes. It's hard to see visible external signs that the cancer is present. Swollen bones are the key sign, so x-rays are often needed to diagnose the cancer.