Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine skin tumor, characterized by high incidence of recurrences and metastases. It is a relatively unusual form of cancer however, its incidence is rapidly increasing.
Therefore, the interest in defining this disease has escalated rapidly. This article addresses what is known and what is still controversial about the pathogenesis, diagnosis and prognostic factors in Merkel cell carcinoma.