Malignant melanoma in situ in two patients treated with psoralens and ultraviolet A.

Two patients are reported who were treated with 8-methoxypsoralen and ultraviolet A (PUVA) for psoriasis and developed cutaneous lesions of malignant melanoma in situ (atypical melanocytic hyperplasia). One patient received 324.5 joules/cm2 of UVA. Seven months after discontinuing therapy, he developed a superficial spreading melanoma in situ in association with an intradermal nevus on the left posterior thoracic area. The second patient received 2,802 joules/cm of UVA. While on PUVA therapy she developed an in situ lentigo melanoma on her lower lip. To our knowledge only one other psoriatic patient and one patient with vitiligo have developed malignant melanomas after PUVA therapy, so that an increased incidence of malignant melanomas after PUVA therapy, so that an increased incidence of malignant melanoma following PUVA is not documented.