title: Clear cells of Toker in accessory nipples.
abstract: BACKGROUND
  Clear cells of Toker are intraepithelial cells with clear to pale staining cytoplasm and bland cytologic features found in approximately 10% of normal nipples. Toker cells have been hypothesized as a precursor of extramammary Paget's disease (EMPD), although the distribution of Toker cells outside of the nipples has not been studied. Using immunohistochemistry, we studied 20 cases of accessory nipples for the presence of Toker cells.
  
  
  METHODS
  A retrospective study of 20 cases of accessory nipples was performed using routine hemotoxylin and eosin staining, as well as immunohistochemical staining for CK7, CK20, EMA, and GCDFP-15.
  
  
  RESULTS
  Thirteen out of 20 accessory nipples (65%) demonstrated Toker cells with CK7 staining. Toker cells in six of the 13 cases were also positive for EMA. Only one case with Toker cells showed immunoreactivity for antibodies to GCDFP-15.
  
  
  CONCLUSIONS
  Toker cells occur outside the normal nipple epidermis in the epidermis of accessory nipples. The distribution of Toker cells along the milk line correlates with the distribution of most cases of EMPD along the milk line, especially in the groin and axillae. Further studies are necessary to define the relationship between Toker cells and EMPD.
authors.affiliation: Department of Pathology, University of Colorado Health Sciences Center, Denver, CO, USA.
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Willman
authors.forename: Loren E
authors.initials: LE
authors.lastname: Golitz
authors.forename: James E
authors.initials: JE
authors.lastname: Fitzpatrick
mesh_terms: D001053:Apolipoproteins; D053399:Apolipoproteins D; D015415:Biomarkers / Q000032:analysis; D002352:Carrier Proteins / Q000378:metabolism; D002828:Choristoma / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006023:Glycoproteins; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D008297:Male; D026901:Membrane Transport Proteins; D018396:Mucin-1 / Q000378:metabolism; D009558:Nipples / Q000002:abnormalities* / Q000378:metabolism; D010145:Paget Disease, Extramammary / Q000209:etiology / Q000473:pathology; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000209:etiology / Q000473:pathology
chemical_list: C024328:APOD protein, human; D001053:Apolipoproteins; D053399:Apolipoproteins D; D015415:Biomarkers; D002352:Carrier Proteins; D006023:Glycoproteins; D026901:Membrane Transport Proteins; D018396:Mucin-1; C488892:PIP protein, human; D007633:Keratins