No one knows what, exactly, causes ear canal tumors, but some believe that long-term inflammation of the ear canal can lead to abnormal tissue development, and the formation of tumors. They can develop from any of the structures along or supporting the ear canal, including the outer layer of skin, the glands that produce earwax and oil, or any of the bones, connective tissues, or middle layers of skin. If your dog has an inflamed ear that doesn’t respond to treatment, it should be inspected by a vet for a tumor.
Ear canal tumors are more common in cats, but not unheard of in dogs. The most common types of benign tumors are inflammatory polyps, papillomas, basal cell tumors, and ceruminous glad adenomas (which are tumors of the glands that produce earwax.) You may notice ear discharge from one ear, a foul odor, head shaking, ear scratching, swelling or draining abscesses near the ear, and deafness.
Symptoms of Ear Cancer in Dogs
– Ear tumors will appear as firm nodules or plaques in the ear canal, opening of the ear, or ear flap. They might be pink, white, or even purplish. Most often, though, they won’t be visible at all without tools. If they grow inside the canal, they can be spotted with a scope. If they grow in the middle or inner ear, a CT or MRI will be necessary to find them.
– There may be bleeding or discharge due to ulceration of the tumor.
– Ear odor may be present.
– Your dog may show itchiness, or appear to be in pain, especially if the middle or inner ear is affected. These kind of tumors may cause mechanical problems. Note any head tilting, shaking, listing to one side or a loss of balance, circling, ear scratching or difficulty breathing.
Causes of Ear Cancer in Dogs
The causes of ear tumors haven’t been pinned down but there are a few theories:
– Evidence suggests that recurrent and long-term inflammation of the ear canal could cause ear tumors. It can lead to abnormal tissue growth and eventually, tumors.
– Some dog breeds, like Pugs, have compressed ear canals. Others have heavy dropping ears that keep the canals covered and moist, causing them to be predisposed to bacterial and yeast infections in the ears. This also leads to inflammation and thickening of the tissues.
– Ear mites can also cause irritation and inflammation. Repeated infestation can lead to the overgrowth of tissue.
– Ear wax glands can excrete thickening secretions when the external ear canal is inflamed and might stimulate the production of cancer cells.
Types
Most ear tumors are polyp-like, and can attach by a narrow base to the outer layer of skin, the glands that produce earwax and oil, or even the bones, connective tissues and muscles. Malignant tumors are more common than benign, but either can develop and appear more often in middle-aged or older dogs. Dogs who have a history of frequent ear infections are at increased risk for ear tumors.
Malignant tumors are locally agressive, and can spread to the nearby lymph nodes, salivary glands, or lungs. Benign tumors tend to grow and compress tissues, but don’t usually spread to other areas. Other cancers can occur in the ear canals or ear flaps, but they’re rarely seen.
Diagnosis of Ear Cancer in Dogs
Blood tests, urinalysis and biopsy will be necessary to determine whether your dog’s ear tumor is benign, or malignant and will spread. Your vet will not be able to tell for certain through observation and physical examination alone. Tumors may be visualized with deep otoscopic examination, which will likely require that your dog be sedated. A CT or MRI might be suggested to determine the extent of the tumor. Biopsies of other areas will let your vet know if a malignant tumor has metastasized.
Treatment of Ear Cancer in Dogs
A benign tumor can be completely removed with surgery. Laser surgery is very effective.
Aggressive surgery is preferred for malignant tumors, and often involves removal of the ear canal and cleaning out the inner ear. This procedure is usually referred to as total ear canal ablation (TECA.) Most dogs can live 2 more years after aggressive surgery.
Radiation therapy might be used to relieve pain and slow the growth of any tumors. It may also be used after the tumor has been surgically removed with the intent of curing.
When a tumor seems aggressive based on the biopsy taken by the vet, or if there is evidence that it has spread, chemotherapy might be recommended. The outlook can be bad should the deep parts of the ear be affected, or if the cancer has spread to the lymph nodes or lungs.
Recovery of Ear Cancer in Dogs
Treating a dog with cancer requires a lot of commitment from an owner. Frequent trips to the veterinary hospital for treatment will take a lot of time and money.
After surgery it’s important to keep the site clean and prevent your dog from fussing with his ears, which will reduce the chance of contamination, infection, bleeding, swelling, and keep him from pulling out his sutures. An e-collar can be a big help. Topical medications might be included, and should be used according to vet’s instructions.
Usually, surgery will lead to a cure, but in others, surgery will only provide a period of remission, with a strong chance that the cancer will return. Keeping your dog as happy and comfortable as possible will be important either way.
