MULTIPLE KERATOACANTHOMAS, GIANT KERATOACANTHOMA AND KERATOACANTHOMA CENTRIFUGUM MARGINATUM - DEVELOPMENT IN A SINGLE PATIENT AND TREATMENTWITH ORAL ISOTRETINOIN

A 78-year-old man is described, who over 18 years developed three diff erent types of keratoacanthoma: multiple keratoacanthomas, keratoacant homa centrifugum marginatum and giant keratoacanthoma. Histological ex amination of the different neoplasms showed similar changes, all typic al of a keratoacanthoma, In situ hybridisation revealed no human papil loma virus in the tumours. Complete examination showed no associated i nternal malignancy. After repeated surgical treatment oral isotretinoi n treatment was administered (1 mg/kg per day). This treatment produce d clearing of existing keratoacanthomas and, during a period of 2 mont hs, further keratoacanthoma formation was completely suppressed, Treat ment was stopped after 3 months by the patient because of side-effects . Numerous keratoacanthomas developed during the following 6 weeks.