Merkel Cell Carcinoma: Epidemiology, Clinical Presentations, Histology, Polyomavirus Involvement, and Management

Merkel cell carcinoma (MCC) is an aggressive cutaneous malignancy with neuroendocrine origin. The rarity of the tumor and variable clinical presentation make the diagnosis especially challenging. The tumor grows rapidly and lymph node metastasis occurs early in the disease course. The etiology is related to prior UV exposure, immunosuppression, and polyomavirus infection. The 2008 discovery of an infectious cause for the majority of Merkel cell carcinoma cases sparked more research into the pathogenesis of the tumor and possible therapeutic options. Although there has been recent improvement, there is a lack of uniform consensus or well-established guidelines on the management of MCC. These difficulties in identifying and treating the disease, as well as the overall poor prognosis, highlight the importance of further research into the area, and the requirement for physicians to stay up to date with the most recent research findings.