2015 Volume 108 Issue 9 Pages 685-691
Pleomorphic adenomas occurring in the external auditory canal are very rare benign tumors, accounting for only 2–3% of benign tumors in this canal. A 29-year-old male visited our hospital with left ear fullness as the chief complaint. The left external auditory canal was filled with a tumor arising from the posterosuperior wall. Temporal bone CT showed a mass obstructing the left external auditory canal but no bone destruction or tumor extension to the middle ear cavity. Biopsy suggested a ceruminous or pleomorphic adenoma. The tumor was excised under local anesthesia using an endaural approach. The skin defect of the external auditory canal after the excision was covered with fibrin glue and a polyglycolic acid (PGA) sheet. The tumor (13×10 mm) was pathologically diagnosed as a pleomorphic adenoma originating from the ceruminous (apocrine) gland, and the surgical margin was negative. His postoperative course was favorable, showing epithelialization of the skin defect of the external auditory canal at about 1 month.
There are two theories concerning the origin of pleomorphic adenomas of the external auditory canal: they originate from myoepithelial cells of the ceruminous (apocrine) gland or from aberrant parotid gland tissue. Since this patient showed ceruminous glands around tumor cells but no parotid gland structures, the tumor was considered to be of ceruminous gland origin. The first treatment choice is surgery. In this patient, the tumor could be excised using an endaural approach that is minimally invasive. A PGA sheet was useful for wound healing in the external auditory canal and the prevention of scar contracture after tumor excision.
