Merkel cell carcinoma: Our experience with seven patients in Korea and a literature review

Background: Merkel cell carcinoma (MCC) is a rare but malignant cutaneous neuroendocrine carcinoma. As MCC has primarily been reported in Caucasians, MCC cases in Korea have not yet been reported. The purpose of this study was to retrospectively review our experience with the surgical treatment of MCC in Korea and to study its management and outcome. Method: We retrospectively reviewed seven MCC case files between 2000 and 2008 from a single institution. We analysed patient characteristics, tumour location and size, staging, treatment methods and outcomes. We performed polymerase chain reaction (PCR) to detect Merkel cell polyomavirus (MCPyV) from formalin-fixed paraffin-embedded tissue specimens. Results: Two patients had stage I tumours, four patients had stage II tumours and one patient had a stage III tumour. Wide local excision with a clear resection margin was the primary modality of treatment in all cases. Adjuvant radiotherapy and chemotherapy were performed for selected patients. Recurrence was observed in two out of the seven cases during the follow-up period. MCPyV was detected by PCR in all seven cases. Conclusion: MCC is an aggressive skin cancer, and pathologic lymph node evaluation is important for staging. Wide excision is the primary modality of treatment, but adjuvant radiotherapy could be positively considered if the tumour is large and the lesion is not confined to the dermis. MCPyV was detected by PCR in all cases, which suggests that MCPyV is also a putative aetiological agent in the carcinogenesis of MCC in Korea.