Abstract

A 65-year-old man, who was exposed to an atomic bomb in Nagasaki 1945, developed an ulcerated tumor on his right upper back in 1995. A squamous cell cercinoma (SCC) was ascertained histopathologically, not only in the back skin but also the right axillary lymph node. Neither of his face nor back skin showed characteristic color changes responsible for actinic damage. Furthermore it is wellknown that SCC occurs rarely in the trunk. These facts do not explain any susceptability of the occurrence of SCC to his back skin. Even though it has passed as many as fifty years after the tragedy by the atomic bomb, the exposure of the extremely huge amount of rays might cause a tumorigenesis.