Merkel Cell Carcinoma: ReviewPulitzer, Melissa P. MD; Amin, Bijal D. MD; Busam, Klaus J. MDAdvances in Anatomic Pathology: May 2009 - Volume 16 - Issue 3 - pp 135-144 doi: 10.1097/PAP.0b013e3181a12f5a Review Articles Abstract Author Information Merkel cell carcinoma (MCC) is synonymous with primary cutaneous neuroendocrine carcinoma. It tends to affects elderly whites, but there is also an increased incidence among immunosuppressed patients. The recent identification of a novel polyomavirus associated with the tumor has stimulated renewed interest in its pathogenesis. MCC tends to show classic histologic features of a neuroendocrine carcinoma and is often positive for CK20, but nonclassic cytologic findings and unusual immunophenotypes may be observed and can lead to a diagnostic confusion. MCC needs to be distinguished from other primary cutaneous tumors with a small cell appearance and metastatic tumors. Surgical excision is the treatment of choice, but radiation therapy has also found to be effective. Sentinel lymph node biopsy has become an integral part of the staging of patients with MCC. Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, NY Reprints: Klaus J. Busam, MD, Department of Pathology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065 (e-mail: firstname.lastname@example.org). All figures can be viewed online in color at http://www.anatomicpathology.com. © 2009 Lippincott Williams & Wilkins, Inc.