A case of giant keratoacanthoma of the auricle.

Although keratoacanthomas are not rare in the head and neck area, patients with this type of tumor rarely consult an otolaryngologists for treatment. Keratoacanthoma should be considered in the differential diagnosis of squamous cell carcinoma. This tumor grows rapidly, usually attaining a size of about 10-20 mm in approximately 6 weeks. This is followed by slow involution over a period of 2-6 months. A keratoacanthoma larger than 20-30 mm is called as 'giant keratoacanthoma' and it is scarce. We encountered a case of giant keratoacanthoma (50 mm in diameter) on the right auricle of 84-year-old Japanese woman with a 3-year history of gradual tumor growth. Several clinical and histopathological factors made the diagnosis difficult. The tumor was completely removed by surgery and diagnosed as a keratoacanthoma by histopathological examination.