Thorium X treatment: multiple basal cell carcinomas within a port-wine stain.

Thorium X is an ionizing radiation treatment that was commonly used by dermatologists in the 1930 s to 1950 s to treat a variety of benign dermatoses and vascular lesions including port-wine stains. By the 1960 s, thorium X was discontinued due to poor clinical results and the carcinogenic potential. We report a 64-year-old man with a history of multiple basal cell carcinomas in a facial port wine stain, which had previously been treated with thorium X.