The human temporal bone occupies the inferolateral skull base. Although osseous, it also possesses an epithelialized ear canal, mastoid, and middle ear, as well as other foramina and canals. Cranial nerves VII to IX, the carotid artery, and the sigmoid sinus all traverse the temporal bone. Almost every type of tissue, from cartilaginous to glandular, can be found within it. Athough any of these structures can give rise to a malignancy, most temporal bone cancers arise from the external auditory canal, and of these, squamous cell carcinoma (SCCA) is the most common.1 Table 53-1 lists a classification of temporal bone malignancies.

It is often difficult to determine the tissue of origin in patients with temporal bone malignancy. Patients with a biopsy-proven ear canal SCCA and an otherwise normal head and neck examination most likely have primary SCCA of the temporal bone. Patients with a prior history of head and neck SCCA who present with a lesion in the temporal bone may have metastatic disease. A diligent search for other evidence of metastases should be sought before embarking on surgical therapy. This might include a contrast computed tomography (CT) scan of the head, neck, and chest. Uncommon lesions such as adenocarcinoma may require a search for metastatic disease, including a thorough breast examination with or without mammography, and a contrast CT scan of the chest, abdomen, and pelvis. Primary tumors metastatic to the temporal bone include carcinoma of the breast, lung, stomach, prostate, and kidney. Of these, most are from the breast.² This chapter focuses primarily on the management of SCCA of the temporal bone. Principles apply to other isolated less common lesions as well, with the exception of pediatric rhabdomyosarcoma, which is treated with limited surgical resection, chemotherapy, and radiotherapy.³

SOURCE : Wenig B, ed. Pathology of the Head and Neck. New York: McGraw-Hill; 1990.

Epidemiology

The incidence of squamous cell carcinoma of the temporal bone is approximately six cases per million in the general population, with most patients more than 50 years of age.⁴ The main risk factor is a long, often two or more decade history of chronic suppurative otitis media.⁵ Other potential inciting factors include chronic dermatitis,⁶ cholesteatoma,⁷ history of employment as a radium dial painter,⁸ and intracranial irradiation.⁹

Clinical and Radiographic Examination

The most common presenting symptom is otalgia; the most common presenting sign is a mass in the external auditory canal.¹⁰ Other clinical manifestations are detailed in Table 53-2

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