Merkel Cell Polyomavirus Infection in a Patient With Merkel Cell Carcinoma: A Case Report

Merkel cell carcinoma (MCC) is a rare and highly aggressive malignancy of the skin which occurs mainly in old people and is very uncommon in young individuals. A new tumor virus belonging to the Polyomaviridae family; Merkel Cell Polyomavirus (MCPyV) has recently been identified in more than 80% of MCCs. We conducted a retrospective review on the archives of the Department of Pathology; Imam Khomeini Hospital Cancer Institute affiliated to Tehran University of Medical Sciences to confirm the MCC samples and we found medical records and samples of a young case with MCC who developed leg skin and scalp tumor six and seven years after bone marrow transplantation, respectively. We analyzed patient formalin-fixed paraffin-embedded samples for the presence of MCPyV DNA using polymerase chain reaction (PCR) method, and the PCR amplicons were subjected to DNA sequencing. Merkel Cell Polyomavirus DNA was detected in both tumors from patient and sequence analysis of the viral LT3 region showed a close homology to strains circulating worldwide. The findings of this study are consistent with the hypothesis that local, systemic, or tumor-induced immunosuppression may allow the MCPyV to initiate skin aggressive cancer. It is necessary to maintain regular check over patients taking immunosuppressive medications for MCPyV infection. Since there is not any information about detection and molecular biology analysis of MCPyV among Iranian patients with MCC, this study provides more information about MCC and MCPyV in Iran.