Atypical presentation of Merkel cell carcinoma positive to polyomavirus DNA detection: Experience from a single center

Abstract

Merkel cell carcinoma (MCC) is a rare malignant tumor of the skin with tendency to rapid local progression and frequent spread to regional lymph nodes. In this paper we retrospectively describe the atypical presentation of 5 cases of Merkel cell carcinoma observed in our surgical department in the last ten years. Four patients had buttock localization whilst one patient had primary nodal presentation. Since integration of Merkel cell polyomavirus (MCPyV) DNA into the tumor genome is frequently recorded in this type of cancer, we analyzed formalin-fixed paraffin embedded MCC tissue samples from our five patients for the presence of MCPyV DNA by means of polymerase chain reaction (PCR). MCPyV DNA was present in all five carcinomas. All patients were treated with wide surgical excision of the tumor and sentinel node biopsy. One patient had stage I disease, three patients had stage II disease, and one patient had stage III disease. Adjuvant radiotherapy was administered in all cases for local control. Chemotherapy was administered to the patient with primary nodal presentation and in stage III disease. Median time of follow-up was 84 months. None of the patients relapsed. Despite the low number of patients examined, our experience suggests that surgery is a necessary step whereas implementation of adjuvant therapy, radiotherapy and chemotherapy depends on individual risk assessment. Treatment outcome was very good, probably due to early detection of MCC.