Foul-Smelling Tumors in Dogs

By Kimberly Kilmer

Dogs are susceptible to a variety of tumors, masses and growths. If masses graduate to an open sore, they can become foul-smelling over time. While only a veterinarian can properly diagnose any mass as a tumor, a tumor that smells bad may also be an abscess. One of the primary symptoms of both open masses and abscesses is odor due to the bodily fluids and infection trapped in or around the mass.

Foul Odor

Masses that produce odor do so because of bacterial or viral infections present on the affected area. A cause of the mass will need to be determined to rid it of the odor. If your dog is producing a foul smell from the skin or any masses on the skin, it's time for a trip to your veterinarian.


An abscess can appear as a tumor. It is caused by infection. Typically, these wounds originate in a dog after the dog has been been bitten by another animal in either the course of play or an altercation. Abscesses can also be the result of injury that produces a puncture-type wound. On heavily coated dogs and outdoor dogs, many times these puncture wounds go unnoticed. Once the skin at the top of the puncture has closed, infection often forms inside the layers of skin, causing a pus pocket or raised mass to form. Some abscesses possess an odor prior to rupture or surgical draining, while others produce a foul odor only after they are opened.

Tumors, Growths and Masses

There are more than 50 different types of both solid and liquid-filled lumps and bumps that can appear on dogs. While not all are tumors, they are often referred as such. These masses range from benign masses to malignant in their properties. While most do not produce foul odor, any when left untreated can produce a foul smell because of a root causes such as bacteria, infection or disease. Common benign and malignant masses that emit an odor are the aforementioned abscess, calluses, sweat gland cysts, granulomas, sebaceous gland tumors, squamous cell carcinomas, follicular cysts, histiocytomas, hematomas and mass cell tumors. These masses can produce odors as they tend to enclose fluid that at times releases from the mass via self-draining tracks.

Skin Conditions

Skin conditions can cause odorous lumps and bumps to appear and a general foul odor to be produced by the skin as a whole. Bacterial infections known as pyoderma and yeast infections called Malassezia dermatitis will produce a generally foul-smelling dog. If left untreated, these infections can cause foul-smelling papules and other masses to form on the skin.

Owner Action

Because many skin masses are cancerous, it is essential that any lump or bump be examined by your veterinarian as soon as you notice it. Early care will most often be kinder not only to your dog, but to your wallet. Many dogs can be quite stoic, so pain or discomfort may not be immediately noticeable. A foul-smelling mass may be no more harmful than one without odor, but immediate care is necessary to diagnose and treat it.