A Case of Squamous-cell Carcinoma Originating in External Auditory Canal Cholesteatoma

External auditory canal cholesteatoma (EACC) is not a rare lesion. Conservative treatment under an operating microscope is appropriate for most cases. On the other hand, squamous-cell carcinoma of middle ear and external auditory canal is less common. We report a case of a 66-year-old man. He suffered from squamous-cell carcinoma following EACC. A biopsy from the external auditory canal was not useful for diagnosis. A biopsy during the first operation revealed squamous-cell carcinoma. The patient was treated by extended radical mastoidectomy and radiotherapy continuously. There is no evidence of recurrence after 14 months.