title: Neurofilament immunoreactivity in Merkel-cell tumors: a differentiating feature from small-cell carcinoma.
abstract: 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.
authors.affiliation: Department of Laboratory Service, Veterans Affairs Medical Centers, Phoenix, Arizona.
authors.forename: I A
authors.initials: IA
authors.lastname: Shah
authors.forename: D
authors.initials: D
authors.lastname: Netto
authors.forename: M O
authors.initials: MO
authors.lastname: Schlageter
authors.forename: C
authors.initials: C
authors.lastname: Muth
authors.forename: I
authors.initials: I
authors.lastname: Fox
authors.forename: R K
authors.initials: RK
authors.lastname: Manne
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D015266:Carcinoma, Merkel Cell / Q000737:chemistry / Q000175:diagnosis*; D018288:Carcinoma, Small Cell / Q000737:chemistry / Q000175:diagnosis*; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D016900:Neurofilament Proteins / Q000032:analysis*; D010751:Phosphopyruvate Hydratase / Q000032:analysis*; D012878:Skin Neoplasms / Q000737:chemistry / Q000175:diagnosis*
chemical_list: D014408:Biomarkers, Tumor; D016900:Neurofilament Proteins; D007633:Keratins; D010751:Phosphopyruvate Hydratase