両側外耳道扁平上皮癌例

Objectives: External auditory canal carcinoma (EACC) is extremely rare, and bilateral cases are even more uncommon. Radiation therapy has been suggested as a possible risk factor. We report a rare case of bilateral EACC, in which contralateral carcinoma developed after surgery and postoperative radiotherapy for the initial lesion. Methods: A 68-year-old woman presented with right otorrhea and otalgia. A mass detected in the right external auditory canal was diagnosed as well-differentiated squamous cell carcinoma (Pittsburgh T1N0M0). She underwent lateral temporal bone resection followed by postoperative radiotherapy (66 Gy). Results: Approximately three years later, the patient developed serous otorrhea and a small mass in the left external auditory canal. Biopsy revealed squamous cell carcinoma (T1N0M0). In deference to the patient’s desire and the need to preserve bilateral hearing, she was treated by chemoradiotherapy with carboplatin (total dose 70 Gy). Local control was achieved without severe adverse effects. Unscientific ear cleaning habits may have contributed to carcinogenesis in the right ear, whereas radiation exposure was considered as a possible risk factor for the contralateral carcinoma. Conclusion: This case illustrates an extremely rare bilateral occurrence of EACC. Early diagnosis and appropriate treatment enabled local control of the disease in the contralateral ear. The case emphasizes the importance of long-term follow-up for cancer recurrence and contralateral occurrence in patients with a history of radiation therapy.