Overview
Any strange lump or bump on a dog should be checked out as soon as possible, especially if the dog is over 6 years old, if the lump has been cut open, if the lump interferes with the dog's normal movements or if the lump is growing quickly. Some dogs grow benign lumps as they get older, but all of the veterinary books listed in the Resources recommend getting them checked out.
Lymphoma
These are lumps on the throat under the skin. They can become malignant. They often happen to older dogs. The ASPCA says that dog breeds like golden retrievers, Airedale terriers and Saint Bernards get lymphoma more often than other breeds. If caught early enough, the dogs can often be cured.
Venereal Tumors
These are passed through direct contact with an infected dog. These tumors are shaped like cauliflowers and appear on the genitals, mouth and nose. Depending on where the tumor is located, they can greatly interfere with the dog's ability to breathe, eat or urinate. The tumors often bleed. These can be curable through radiation therapy and chemotherapy. "Dog Owner's Home Veterinary Handbook" notes that surgery is not often performed for these tumors.
Breast Cancer
According to the "Dog Owner's Home Veterinary Handbook," this is the most common cancer in older, unspayed female dogs, preventable by spaying. They are also called mammary gland tumors. These lumps will vary in size and looseness, but usually they are under the skin. They can be solitary or come in groups. The sooner the lump is detected, the better the dog's chance of survival.
Melanoma
These tumors can occur anywhere on the dog's skin, in the mouth or at the base of the claws. A biopsy is necessary to determine if the tumors are malignant or benign. They are often brown or black and tend to be round. Most melanomas in the mouth or at the base of the claws are malignant.
Perianal Tumor
This happens around the rectum of older unnetuered male dogs. They often aren't malignant, but can certainly interfere with your dog's ability to have a bowel movement. They appear most often in Siberian huskies. These can be removed by surgery.
Resources
