Merkel Cell

  • Ectoderm-derived cell (less likely neural crest-derived) functioning as mechanoreceptor (slow adapting, type I); found among basal keratinocytes and positive for S100 immunostain
  • Found in areas with high tactile sensitivity (lips, fingers, ORS of hair follicle, oral mucosa)
  • EM shows microvilli at cell surface with dense core granules, lobulated nucleus, and intermediate filaments assuming whorled arrangement near nucleus (dot-like pattern)
  • Markers: cytokeratin (CK) 20 (specific for merkel cells in skin), also contain CK8, 18, and 19
  • Contain battery of neuropeptides and neurotransmitter-like substances:
    • Neuron-specific enolase (NSE), vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), chromogranin A, synaptophysin, and met-enkephalin