A case of Merkel cell carcinoma in association with Bowen's disease

Merkel cell carcinoma is an uncommon malignancy of the skin that was first described by Toker in 1972 and occasionally found concurrent with other malignancies such as squamous cell carcinoma, basal cell carcinoma or, as in the present study, with Bowen's disease. We report a unique case of Merkel cell carcinoma coexisting with Bowen's disease on the left forearm of a 42-year-old man who had a past history of multiple Bowen's disease. The tumor was excised and the specimen was examined histopathologically. The tumor cells exhibit trabecular, cord-like arrangement in the dermis, partly extending into subcutaneous tissue without involvement overlying epidermis, where Bowen's disease lesion was absent but the peripheral patch area exhibit Bowen's disease. The tumor cells in the dermis were positive for neuron-specific enolase and chromogranin. This is the first report of a case of Merkel cell carcinoma associated with Bowen's disease in Korea.