Mule spinner's disease.

Mule spinner's disease represents the occurrence of scrotal cancer in cotton textile workers exposed to mineral oils on a long-term basis while working on a machine called "the mule." We describe a 66-year-old cotton textile worker who had frequent scrotal contact with mineral oils and later had multiple squamous cell carcinomas of the scrotum develop. He also had a variety of other keratotic lesions develop on the scrotum that histopathologically demonstrated features of verruca, lichenoid keratoses, and squamous cell carcinomas in situ. We have termed these lesions mule spinner's keratoses.