Keratoacanthoma centrifugum marginatum.

A keratoacanthoma centrifugum marginatum measured 20 X 14 cm at the time of surgical intervention. This lesion is characterized by continuing peripheral extention and central healing. Attention is drawn to the occurrence in the healing edge of a distinctive type of individual cell necrosis, which has been described by others in the more usual forms of keratoacanthoma. The findings are of interest, since this same mode of cellular death has recently been shown to be involved in the regression of various tissues, normal as well as abnormal.