[Two cases of osteoma of the external auditory canal].

The tumors of the external auditory canal are relatively rare. Among these tumors an osteoma is not common. Two cases of osteoma of the external auditory canal were reported. The patient, 26-year-old female, had a history of left-sided hearing impairment and w hard mass protruding from the posterior part of the left external canal. A stony hard mass almost completely occlu ded the left external canal. The sessile tumor covered with normal skin, which was found to be attached to the posterior wall, was removed by means of retroauricular partial mastoidectomy. The histologic examination revealed a solitary osteocartilaginous tumor. The other patient, 17-year-old female, suffered from tinnitus and earache of the right ear. A bony tumor, covered with gray-whitish skin, completely occluded the right external auditory canal. It was removed by means of retroauricular incision. The histopathologic examination revealed osteoma. The two lesions, osteoma and exostosis, have been defined and reviewed the literatures. Osteoma of the external auditory canal is a solitary unilateral pedunculated lesion, attached to the tympanosquamous suture or to the tympanomastoid suture. By contrast, exostosis of the external canal is broad-based elevation of bone, usually multiple and bilaterally symmetrical, located deeply to the isthmus, at the upper edges of the tympanic bone. ŠOŽ ̈“1•œŽî‚Ì2•Ç—á ‰aŽR‘åŠw•”Ž ̈•@ˆô•A‰ÈŠw‹3Žo(Žå”C:•‚Œ ́Ž •v‹3Žö)••‹3Žö•¬‘q‹` ̃Y•u•ƒ’|–{•F