Multiple keratoacanthoma centrifugum marginatum.

Keratoacanthoma centrifugum marginatum (KCM) is a rare variant of keratoacanthoma characterized by a progressive peripheral growth with concomitant central healing. We report here a case of multiple KCM of the lower legs in a 48-year-old man. The lesions had progressively evolved over 3 years. They were multiple asymptomatic and confluent annular plaques of 5 to 20 cm, having papulo-nodular with hyperkeratotic and crusted borders and cicatricial center. Within the centers were numerous firm and pigmented minipapules of 1 to 2 mm. The typical clinical aspect, together with characteristic histological features confirmed the diagnosis of KCM. Herein we will highlight the clinical and histological features of KCM, as well as the different effective treatments. We will also briefly discuss KCM among the other types of keratoacanthomas.