Merkel cell carcinoma: A review

Abstract

Merkel cell carcinoma has been a focus of active scientific investigation in recent years and new information on the topic has emerged. Although uncommon, this primary cutaneous neuroendocrine carcinoma, usually involving the head/neck of elderly individuals, has a poor prognosis. Within the past two decades, an increase in the incidence of the tumor and the discovery of its link to the Merkel cell polyomavirus have focused medical attention on the lesion. The resulting studies have improved our understanding of the biology of the neoplasm and contributed to clinical care. Specifically, two pathogenic subsets of the tumor have come to light, the majority due to Merkel cell polyomavirus and the minority caused by ultraviolet radiation‐induced genetic damage. This dichotomy carries prognostic implications favoring the former subset. In addition, having capitalized on the known susceptibility of the tumor to immune influences, investigators have recently discovered its responsiveness to immune checkpoint inhibition. This revelation has constituted a therapeutic milestone at the clinical level. Herein we provide an overview of the topic, outline updates in the field and place an emphasis on dermatopathologic aspects of Merkel cell carcinoma.

Merkel Cell Carcinoma

“…MCC is more common in males and elderly fair-skinned individuals subjected to chronic sun exposure. Moreover, the risk for developing MCC is increased in immunocompromised patients (e.g., chronic lymphocytic leukemia, HIV/AIDS, medical treatment for autoimmune diseases, solid organ transplantation and other types of cancers) [4][5][6].…”

“…MCC typically presents as a rapidly growing, erythematous lesion in the dermal layer of the skin [4][5][6]. The acronym AEIOU accounts for 90% of all MCC presentation: asymptomatic, expanding rapidly, immune suppression, older than 50 years, and ultraviolet (UV) radiation-exposed [7].…”

“…Besides rapid local growth, systemic tumor progression is also fast. In fact, MCC frequently metastasizes to the lymph nodes and distal organs, including liver, bone, pancreas, lung, and brain [4][5][6]. As patients are often elderly and the metastatic potential of the tumor is high, MCC prognosis is poor [4][5][6].…”

“…Because of MCC's aggressiveness, a multidisciplinary evaluation of patients is critical in outlining the therapeutic choice. In fact, appropriate management typically involves a combination of surgery, radiation, and chemotherapy [4][5][6]. Recently, advanced MCC has been treated with immune checkpoint inhibitors (ICI), demonstrating their remarkable efficacy [4][5][6]9,10].…”

“…In fact, appropriate management typically involves a combination of surgery, radiation, and chemotherapy [4][5][6]. Recently, advanced MCC has been treated with immune checkpoint inhibitors (ICI), demonstrating their remarkable efficacy [4][5][6]9,10].…”