Ear Cancer (Adenocarcinoma) in Dogs

Ceruminous Gland Adenocarcinoma of the Ear in Dogs

More common in cats than dogs, ceruminous gland adenocarcinoma is the primary malignant tumor of the sweat glands that is found in the external auditory canal. Though rare, it is one of the most common malignant tumor of the ear canal in older dogs. And while it may be locally invasive, it has a low rate of distant metastasis (spreading of the cancer).

In addition, there is no known gender predisposition for this type of tumor, but Cocker spaniels may be more at risk.

Symptoms and Types

Similar to otitis externa, dogs with ceruminous gland adenocarcinoma exhibit vestibular signs such as dizziness, tilting of the head, uncoordination, and frequent stumbling. Local lymph node enlargement may also be seen. Other symptoms depend on the stage of the cancer.

Early stages of nodular masses:

• Pale pink
• Break off easily
• Open ulcers
• Bleeding

Later stages:

• Large mass(es) which fill the canal and invade through the canal wall into surrounding structures

Causes

Experts are still uncertain of the exact cause for this type of adenocarcinoma, but chronic inflammation may play a role in tumor devlopment.

Diagnosis

Your veterinarian will perform a thorough physical exam on your dog, taking into account the background history of symptoms and your dog’s health history leading up to the onset of symptoms.Standard tests include a complete blood profile, chemical blood profile, a complete blood count, and a urinalysis.

Radiographic and CT (computed tomography) imaging are essential to confirming the diagnosis. Skull X-rays, for example, can help to determine if the tympanic bullae (the bony extension of the temporal bone in the skull) are involved in the mass. And thoracic X-rays and CT scans help identify if the cancer has spread (metastasized) to other organs. A tissue sample for biopsy will be essential for determining the exact nature of the growth.