Abstract: Individuals with long-term arsenic environmental exposure have a significantly increased risk of developing skin tumors, with common types including Bowen's disease, squamous cell carcinoma, and basal cell carcinoma. We report a 38-year-old male who had taken arsenic-containing traditional Chinese medicine orally for 1 year during adolescence to treat osteomyelitis. Twenty years later, he concurrently developed cutaneous Merkel cell carcinoma, squamous cell carcinoma, Bowen's disease, and arsenical keratosis. A history of arsenic exposure may be associated with the development of multi-site skin tumors.

Key words: Merkel cell carcinoma, Bowen's disease, squamous cell carcinoma, arsenical ketatosis, arsenic