There are all too many tumors that can form deep within your dog’s body — in bones or tissue, or within organs like the heart, liver, and kidneys — without your knowledge. But some tumors in dogs can be detected by a pet parent during grooming, while petting your dog, or through simple visual observation. And while it can be scary every time you find a new lump or bump on your pet, not all tumors are problematic. Many are benign, and some are easily treated even if cancerous.
If you do spot a change in your dog’s appearance, it’s very important to visit the vet to find the cause and decide if any treatment is required. Below are some tumors that you might find through touching or looking at your dog.
1. Mammary-Gland Tumors
You’ll rarely find these tumors in unspayed females, but if your dog has not been spayed, these tumors are fairly common. The tumor can be detected by touch, can be large or small in shape, and they are most often located in the glands closest to a dog’s groin. Larger tumors — sized at more than an inch and a half — tend to have a worse prognosis. Tumors that are attached to the skin often are cancerous, whereas tumors capable of being moved with your fingers are more likely to be benign.
2. Testicular Tumors
Testicles that are enlarged, or the presence of one testicle that is larger than another, is often a likely tip-off to testicular cancer. If you notice any change in the shape of a dog’s testicles, get in touch with a vet for an examination. Note that dogs with undescended testicles are very likely to develop testicular cancer, so if that is this case with your dog, be vigilant to swelling of the descended testicle or your dog’s abdomen. Neutered dogs can’t develop testicular cancer.
3. Mast Cell Tumors
One of the most common skin tumors in dogs, mast cell tumors are raised growths that appear on your dog’s skin. Tumors caused by mast cells are cancerous — your vet can determine if a lump on your dog’s skin is the result of mast cell growth through a needle aspiration of the lump.
If you spot a bright red hairless bump on your dog’s skin, you may feel alarmed, particularly since histiocytomas often appear very suddenly — even overnight. The good news is that histiocytoma tumors are benign. However, as with any bump, it’s always recommended that you have a vet diagnose the issue, since other red or hairless bumps can be problematic.
These cancerous tumors occur from blood cells, and while they commonly appear within internal organs like the liver and heart, they can also occur on a dog’s skin. Most commonly, hemangiosarcomas on the skin will appear on a dog’s hind legs or neck, or any body part that is hairless. They are very often red or black in color, and can be treated with a combination of surgery and chemotherapy.
Melanomas are dark in color — usually black or brown — and look a lot like moles. These marks can appear on the eyelids, nail bed, mouth, or skin of dogs. While some are benign, others are malignant, so it’s important to check in with the vet, since appearance alone cannot reveal the status of the mole-like mark.
These fatty skin tumors are benign, and appear on the subcutaneous layer of a dog’s skin, often on the neck or belly. These tumors have a soft feel — not firm — and can be moved.
8. Basal Cell Tumors
These tumors are quite common in dogs. Often there is just one of these tumors, and although their size varies, they are usually hairless and raised above the skin. You’ll spot these tumors on a dog’s neck or shoulders. Generally, they are not malignant, and can be surgically removed.
9. Squamous Cell Carcinoma
These tumors are a result of sun exposure, and generally occur in hairless areas on your dog. They can be a variety of colors — red, white, or gray. More often than not, these tumors are malignant and need to be surgically removed.
Also known as lymphosarcoma, this cancer of the lymph nodes has several classification types. Multicentric lymphoma, the most common variety for dogs, is characterized by swollen glands at the dog’s neck. Although there is no cure for lymphoma, chemotherapy is used to reduce symptoms and extend a dog’s life.
Keep an eye out for growths and swollen areas on your dog — while some will be nothing to worry about, it’s a good idea to follow up on any physical changes in your dog’s appearance with the vet.
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This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.