title: Immunohistochemical analysis of cytokeratin and human milk fat globulin expression in mucinous carcinoma of the skin.
abstract: BACKGROUND
  Mucinous carcinoma of the skin (MCS) is a rare epithelial tumor which arises primarily in the skin. Metastatic MC from extracutaneous sites, especially breast or colon, mimics MCS and cannot be differentiated from MCS by routine histology alone.
  
  
  METHODS
  Nine cases of MCS were analyzed immunohistochemically using monoclonal antibodies against cytokeratins (CKs) and human milk fat globulin 1 (HMFG) in order to clarify their nature and compare the immunophenotypes with those of other MCs studied in the literature.
  
  
  RESULTS
  Expression of simple epithelial CKs in most of the tumor cells of all cases studied and co-expression of simple and stratified epithelial CKs in some tumor cells of two cases were recognized. CK 20 expression could not detected in any tumor cells. Focal HMFG expression in the luminal or outer surface of the nests was observed in three cases.
  
  
  CONCLUSIONS
  From CKs expression, MCS was speculated to differentiated mainly toward the secretory cells of the sweat glands, and some tumor cells toward the transient portion between the dermal duct and the secretory portion. Focal HMFG expression suggested either a consequence of malignant transformation or apocrine differentiation. No expression of CK 20 in MCS suggests that we may exclude the diagnosis of metastatic colorectal MC which expressed CK 20.
authors.affiliation: Department of Dermatology, Teikyo University School of Medicine, Tokyo, Japan.
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Ohnishi
authors.forename: Hajime
authors.initials: H
authors.lastname: Takizawa
authors.forename: Shinichi
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000378:metabolism* / Q000473:pathology; D000328:Adult; D000368:Aged; D000951:Antigens, Neoplasm / Q000032:analysis; D014408:Biomarkers, Tumor / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000096:biosynthesis*; D007782:Lactoglobulins / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D012878:Skin Neoplasms / Q000378:metabolism* / Q000473:pathology
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D007782:Lactoglobulins; D007633:Keratins