title: A malignant neoplasm with features of both squamous cell carcinoma and malignant melanoma.
abstract: A case of a malignant neoplasm with features suggestive of both malignant melanoma and squamous cell carcinoma is reported. The neoplastic cells were positive for both S-100 protein and keratin when stained by the indirect peroxidase-antiperoxidase method. The literature on other instances of bi- or multidirectional differentiation of neoplastic cells is reviewed. The significance of these findings for terminology of neoplasms is discussed.
mesh_terms: D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000648:ultrastructure; D005153:Facial Neoplasms / Q000473:pathology* / Q000648:ultrastructure; D005260:Female; D006801:Humans; D007633:Keratins / Q000032:analysis; D008545:Melanoma / Q000473:pathology* / Q000648:ultrastructure; D009378:Neoplasms, Multiple Primary / Q000473:pathology* / Q000648:ultrastructure; D009418:S100 Proteins / Q000032:analysis
chemical_list: D009418:S100 Proteins; D007633:Keratins