Merkel cell carcinoma: what do we know about it and what should we do?

Merkel cell carcinoma (MCC) is a rare primary cutaneous carcinoma of the skin that is highly aggressive, and has a high risk of locoregional and distant spread, a mortality rate considerably higher than that of cutaneous melanoma and poor survival. Its incidence has increased during the past twenty years. The studies published since 2008 have introduced changes in the understanding of its epidemiology and pathogenesis, and consequently the therapeutic approach. Despite this, there is still controversy surrounding its optimal management, which requires clarification. This is the purpose of this review.