A skin disease marked by scaly or thickened patches on the skin, and often caused by prolonged exposure to arsenic. The patches often occur on sunexposed areas of the skin and in older white men. These patches may become malignant (cancerous). The phenotype is cutaneous precancerous condition (EFO_0006892). Also known as: cutaneous premalignant condition, precancerous dermatosis, precancerous skin lesion.