Radiation-induced squamous carcinoma arising within a seborrhoeic keratosis.

Seborrhoeic keratoses (SK) are common skin tumours. They are benign, and present little difficulty in management. However, rare malignant transformation is recognized. We report a case of a squamous cell carcinoma arising from dysplastic changes within a long-standing SK on the chest wall of a 75-year-old retired radiologist, and consider the role of radiation in inducing malignant change within SKs.