Tumor Spread from Temporal Bone

Epidemiology

Carcinoma of the temporal bone is uncommon and represents < 1% of all head and neck neoplasms. Most of these tumors arise in the external auditory canal (EAC), whereas tumors originating in the middle ear cavity are very rare. These tumors occur in middle- and older-age groups. The etiology is unknown but appears to be related to chronic ear infection and exposure to ionizing radiation.

Pathology

The histological appearance of squamous cell carcinoma of the EAC and the middle ear is similar to lesions of squamous cell carcinoma elsewhere. Early lesions are confined within the EAC. Neglected lesions cause massive temporal bone destruction with intracranial extension and spread to the skull base. Skull base extension may lead to parapharyngeal extension.

Clinical Findings

Squamous cell carcinoma of the EAC typically presents as a soft tissue mass in the EAC. Bleeding is common and there may be concomitant signs of infection. The presence of other signs such as hearing loss, vertigo, or CN VII palsy depends on tumor extent.