Adenoid cystic carcinoma involving the external auditory canal. A clinicopathologic study of 16 cases

Sixteen patients with a rare tumor, adenoid cystic carcinoma (ACC) involving the external auditory canal, have been studied. Clinically, most patients complained of ear pain, often of several years duration. On physical examination, a mass or a nodule usually was identified in the ear canal. In most cases, treatment consisted of a wide surgical resection of the auditory canal and adjacent structures. Histologically, these neoplasms had the same appearance as ACC originating in salivary glands. In eight cases, the tumor was confined to the ear canal wall and unquestionably arose in this area, probably within the ceruminous glands. When incompletely excised, these lesions usually recurred locally. Nine patients had a total of 26 local recurrences. Most recurrences were found within two years of the preceding treatment, but the interval in some cases was long, ranging up to 14 years. Of the 16 patients, seven had no evidence of recurrence following surgical resection, two were living with recurrent, unresectable tumor, five had died of disease, one had died of other causes, and one was lost to follow-up. Some patients died of tumor after a prolonged clinical course with multiple recurrences. Death usually was caused by intracranial extension by the tumor, or by pulmonary metastases. Radiotherapy did not appear to cure the lesion, but probably resulted in palliation. An increased incidence of recurrent, unresectable tumor or of death from the neoplasm correlated with the following histologic features: demonstration of tumor on the lines of surgical excision, involvement of the parotid gland, extension into bone, perineural invasion and local recurrence of tumor.