Which histopathologic features of a Merkel cell carcinoma (MCC) tumor differentiate it from similar cancers?

Updated: Jan 18, 2019
  • Author: Arjun S Joshi, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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The cells possess hyperchromatic nuclei, minimal cytoplasm, and frequent mitotic and apoptotic figures, which suggest a rapid growing neoplastic process. MCC cells positive for Merkel cell polyomavirus (MCV) may have less nuclear polymorphism and less cytoplasm than their MCV-negative counterparts. [15]

MCC can resemble and be confused with other poorly differentiated small cell carcinomas, such as metastatic small cell carcinoma of the lung, Ewing sarcoma, neuroblastoma, melanoma, or basal cell carcinoma.

As the tumor advances, it infiltrates into underlying subcutaneous fat, fascia, and muscle. Vascular and lymphatic invasion is common.

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