title: Toker cells of the nipple are commonly associated with underlying sebaceous glands but not with lactiferous ducts.
abstract: OBJECTIVE
  Toker cells are clear cells present in the squamous epithelium of the nipple of some women. In contrast to squamous epithelium, they are cytokeratin 7 (CK7) positive. The origin of these cells is not completely understood. It has been suggested that they may represent abortive glands or migratory ductal cells; and may be precursors of Paget's disease of the nipple. Our aim was to investigate the incidence and distribution of Toker cells and their relationship with lactiferous ducts.
  
  
  METHODS
  We examined nipple sections from 100 consecutive mastectomies performed at Charing Cross hospital. New sections were stained for CK7 using the immunoperoxidase technique.
  
  
  RESULTS
  Toker cells were identified in 11 cases. They were always clustered within the squamous epithelium superficial to sebaceous glands with no relationship with lactiferous ducts. Two cases in the study had Paget's disease and these were not associated with underlying sebaceous glands.
  
  
  CONCLUSIONS
  This study suggests that Toker cells are more likely to be developmentally related to sebaceous glands rather than lactiferous ducts. This raises doubts about the presence of a relationship between Toker cells and the common forms of Paget's disease, as the latter are commonly seen in association with ductal carcinoma in situ (DCIS) involving underlying lactiferous ducts. Toker cells, however, may be related to a less common form of Paget's disease which is not associated with underlying DCIS.
authors.affiliation: Department of Histopathology, Charing Cross Hospital, Imperial College Healthcare NHS Trust and Imperial College, London, UK.
authors.forename: Duaa
authors.initials: D
authors.lastname: Saeed
authors.affiliation: Department of Histopathology, Charing Cross Hospital, Imperial College Healthcare NHS Trust and Imperial College, London, UK.
authors.forename: Sami
authors.initials: S
authors.lastname: Shousha
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D001943:Breast Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053552:Keratin-7 / Q000032:analysis; D008131:London; D042361:Mammary Glands, Human / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D008408:Mastectomy; D008875:Middle Aged; D009558:Nipples / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D010144:Paget's Disease, Mammary / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D012627:Sebaceous Glands / Q000737:chemistry / Q000473:pathology* / Q000601:surgery
chemical_list: D015415:Biomarkers; C507497:KRT7 protein, human; D053552:Keratin-7
keywords: BREAST; BREAST CANCER; BREAST PATHOLOGY; HISTOPATHOLOGY; IMMUNOCYTOCHEMISTRY