The prevalence of Merkel cell polyomavirus in Japanese patients with Merkel cell carcinoma.

Background: A novel polyomavirus, the Merkel cell polyomavirus (MCPyV) has been implicated in the pathogenesis of Merkel cell carcinoma (MCC); however, the prevalence of MCPyV in Japan has not been extensively investigated.

Objective: To clarify the prevalence of MCPyV in Japanese patients with MCC.

Methods: MCPyV DNA was examined by polymerase chain reaction (PCR) in formalin-fixed paraffin-embedded (FFPE) or frozen tissue samples from 26 patients with MCC diagnosed in four medical centers in Japan.

Skin metastasis of dermatofibrosarcoma protuberans with distinct morphological features, confirmed by COL1A1-PDGFB fusion gene analysis.

We discuss a metastatic dermatofibrosarcoma protuberans on the occiput of a 53-year-old man whose initial tumor appeared on his forehead 23 years previously. The pathology of the tumor that recurred at the initial site was fibrosarcomatous dermatofibrosarcoma protuberans, whereas the metastatic tumor was a pigmented dermatofibrosarcoma protuberans, the so-called Bednar tumor. Because both tumors possessed the identical chimeric COL1A1-PDGFB fusion gene, the metastatic nature of the occipital tumor was confirmed.