Neurofilament immunoreactivity in Merkel-cell tumors: a differentiating feature from small-cell carcinoma

Mod Pathol. 1993 Jan;6(1):3-9.


To differentiate Merkel-cell tumor (MCT) from other neuroendocrine (NE) carcinomas, we immunostained (using avidin-biotin-peroxidase method) nine MCT and 37 NE (including 28 small-cell) carcinomas for NE markers (neuron-specific enolase and chromogranin), cytokeratin, neurofilament, vimentin, and a number of other markers. Cytokeratin was positive in 100% of MCT and in 85% of small-cell carcinomas; neurofilament and vimentin were positive in respectively 100% and 22% of MCT and 0% of NE carcinomas. Our data suggest that the coexpression of cytokeratin and neurofilament by an undifferentiated dermal or visceral tumor is of significant help in diagnosing MCT and differentiating it from small-cell carcinomas. The vimentin reactivity is a weak and insignificant discriminant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / analysis*
  • Carcinoma, Merkel Cell / chemistry
  • Carcinoma, Merkel Cell / diagnosis*
  • Carcinoma, Small Cell / chemistry
  • Carcinoma, Small Cell / diagnosis*
  • Diagnosis, Differential
  • Humans
  • Immunohistochemistry
  • Keratins / analysis*
  • Male
  • Middle Aged
  • Neurofilament Proteins / analysis*
  • Phosphopyruvate Hydratase / analysis*
  • Skin Neoplasms / chemistry
  • Skin Neoplasms / diagnosis*


  • Biomarkers, Tumor
  • Neurofilament Proteins
  • Keratins
  • Phosphopyruvate Hydratase