Multiple skin cancers in a single patient: Multiple pigmented Bowen's disease, giant basal cell carcinoma, squamous cell carcinoma.

Basal cell carcinoma (BCC) and squamous cell carcinoma are the most common type of nonmelanoma skin cancers (NMSCs). Bowen's disease (BD), a premalignant condition, has a marginal potential (3-5%) to progress to invasive carcinoma. We report here a rarest of a rare case of multiple pigmented BD with overlying squamous cell cancer along with a giant neglected BCC on the scalp of a 76-year-old man. The occurrence of multiple BD and NMSC in a single patient compelled us to explore the following hypothesis: (1) The multiple precancerous and cancerous lesions can be due to common etiopathogenesis. Chronic ultraviolet exposure, immunosupresssion, human papillomavirus infection, dietary factors, and environmental factors including arsenic exposure were probed in to. (2) There is evolution of precancerous lesions into a different type of cancers in different time frame. (3) The new cancerous lesions are subsequent cancers that developed after neglected untreated primary cancer.