Ear Canal Tumors in Dogs

Ear canal tumors are abnormal growths that arise from any part of the ear canal. Both malignant and benign ear canal tumors are uncommon. Benign tumors do not spread; malignant tumors commonly spread to adjacent tissues or other parts of the body. Ear canal tumors are uncommon.

Any pet that is experiencing odorous discharge from the ear, shaking of the head, or ear scratching needs to be examined by a veterinarian as soon as possible. Diagnosis and treatment are usually straightforward but often involve surgery. Prognosis varies depending on whether or not the tumor is benign or malignant.

Middle-aged to older pets have a higher incidence of ear canal tumors. Breeds such as Cocker Spaniels, Boxers, and German Shepherds are over-represented which may be related to their higher incidence of ear canal infections.

Symptoms vary based on what structures have been affected.

The underlying cause of many types of ear canal tumors cannot be determined. However, recurring ear infections and chronic inflammation are risk factors for developing ear canal tumors.

Benign ear canal tumors include:

• Papilloma
• Basal cell tumor
• Ceruminous gland adenoma

Malignant ear canal tumors include:

• Ceruminous gland adenocarcinoma
• Squamous cell carcinoma

Ceruminous gland adenomas occur on the head, pinna, and in the ear canal. Ceruminous gland adenocarcinomas typically arise within the ear canal and can invade the middle ear. Ceruminous gland adenocarcinomas are the most common type of malignant neoplasm found in the ear canal.

Common symptoms of ear canal tumors are

• Visible mass or deformity within the ear canal
• Shaking of the head
• Scratching at ears
• Odorous discharge from ears
• Hearing loss

Benign tumors are usually smooth, raised, and are rarely ulcerated. It is common for malignant tumors to become ulcerated and bleed.

Initial diagnostic steps include physical and otoscopic exams. Endoscopic evaluation of the ear canal under anesthesia may be needed to visualize and sample (cytology or biopsy) the mass. Cells from the mass are sent to a pathologist for evaluation to obtain a definitive diagnosis. Definitive diagnosis of tumor type is imperative for prognosis and planning treatment.

Advanced diagnostic imaging like a CT of the head can be used to ascertain if the tumor has spread and what structures are involved. Additional screening tests such as blood work, urinalysis, radiographs of the lungs, and abdominal ultrasound are also recommended.

Surgical removal of the tumor is curative with benign tumors. Malignant tumors require surgical removal and adjunct therapy such as chemotherapy or radiation.

Secondary infections are very common with ear canal tumors. Ear canal cytology, ear canal culture, and antimicrobial medication are often needed to resolve infections prior to surgical removal.

Benign tumors are slow growing, but often lead to irritation and repeated infections. Malignant tumors are life-threatening and continue to spread and invade tissue until they are removed.

Prognosis for benign ear canal tumors is good with complete surgical removal. Prognosis for malignant tumors is dependent on structures affected and spread to other parts of the body, but is generally considered poor.

Several weeks to months are usually required from the point of initial diagnosis through recovery from surgery.

Prevention of ear infections and quick, consistent, and thorough treatment for infections may help prevent ear canal tumors.

Ear canal tumors are not contagious.

Ear canal tumors are uncommon.

Treatment consists of:

• Surgical removal of tumor
• Radiation
• Chemotherapy