What is Merkel cell carcinoma (MCC)?

Merkel cell carcinoma (MCC), also known as primary neuroendocrine carcinoma of the skin, is an aggressive malignant neoplasm. The tumor was initially thought to arise from Merkel cells, receptors of mechanical stimuli with a high density on hairless skin. However, the tumor is now thought to arise from a less–well-differentiated progenitor cell of probably epithelial origin.