Malignant melanoma at sites of therapeutic X-irradiation.

Two patients are reported in whom malignant melanoma developed at sites of low-dose superficial X-ray therapy given for treatment of benign dermatoses. No causal link has been established between melanoma and X-irradiation, but previous reports of a possible association are reviewed. The probably importance of ultraviolet exposure after X-irradiation in such patients is emphasised.