Reactive lentiginous hyperpigmentation after cryosurgery for lentigo maligna.

Abstract

Twenty patients treated for lentigo maligna of the face with cryosurgery developed benign lentiginous hyperpigmentation mimicking a recurrence. When cryosurgery is used in the treatment of lentigo maligna, it is important to know whether repigmentation of the scar represents true recurrence or a benign process. Twenty patients were treated with cryosurgery for lentigo maligna of the face. Within a follow-up period of 7 to 80 months, frequent clinical observations were made. Lentiginous hyperpigmentation developed within the treatment area in eight patients. Histologic investigation revealed recurrence of lentigo maligna in three and benign hyperpigmentation in five. Genetic factors and UV exposure after cryosurgery may favor the development of benign lentiginous hyperpigmentation. Because recurrence of lentigo maligna must be considered, histologic evaluation of repigmentation is mandatory.