Ear Cancer (Adenocarcinoma) in Cats

Ceruminous Gland Adenocarcinoma of the Ear in Cats

Ceruminous gland adenocarcinoma is the primary malignant tumor of the sweat glands found in the external auditory canal. Though rare, it is one of the most common malignant tumor of the ear canal in older cats. 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 it is more common in cats than dogs.

Symptoms and Types

Similar to otitis externa, cats with ceruminous gland adenocarcinoma exhibit vestibular signs such as dizziness, tilting of the head, uncoordination, and frequent stumbling or falling. 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



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


You will need to give a thorough history of your cat’s health, including the onset and nature of the symptoms, to your veterinarian. Your doctor  will then perform a complete physical examination as well as a biochemistry profile, urinalysis, complete blood count (CBC), and an electrolyte panel.

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.

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