New Insights Into Merkel Cell CarcinomaCalder, Kenneth B. MD*; Smoller, Bruce R. MD† ‡Advances in Anatomic Pathology: May 2010 - Volume 17 - Issue 3 - p 155-161 doi: 10.1097/PAP.0b013e3181d97836 Review Articles Buy Abstract Author InformationAuthors Article MetricsMetrics Merkel cell carcinoma (MCC) is a rare aggressive cutaneous malignancy of the elderly and immunocompromised populations. The clinical presentation of MCC is nonspecific, with the majority of cases presenting as localized skin involvement. Histologically and immunophenotypically, MCC is defined by both neuroendocrine and epithelial differentiation. Recently, the Merkel cell polyomavirus has been implicated in the pathogenesis of MCC. In addition, there have been numerous studies evaluating the histologic and immunohistochemical characteristics of MCC as they relate to diagnosis and prognosis. The purpose of this paper is to review the most salient and clinically relevant updates in the pathogenesis and histologic features of MCC. Specific attention is given to the clinical and histologic predictors of prognosis, staging, and the controversies concerning sentinel lymph node biopsy and therapy. *Department of Pathology and Cell Biology, University of South Florida, Tampa, FL Department of †Pathology ‡Dermatology University of Arkansas for Medical, Sciences, Little Rock, AR Reprints: Kenneth B. Calder, MD, Department of Pathology, University of South Florida, 12901 Bruce B. Downs Blvd., MDC Box 11, Tampa, FL 33612 (e-mail: firstname.lastname@example.org). All figures can be viewed online in color at http://www.anatomicpathology.com. The authors have no conflicts of interest with any commercial interest and no funding was received. © 2010 Lippincott Williams & Wilkins, Inc.