title: Immunohistochemical distinction of primary sweat gland carcinoma and metastatic breast carcinoma: can it always be accomplished reliably?
abstract: OBJECTIVE
  Even with adequate history, the distinction of cutaneous metastatic breast carcinoma from primary sweat gland carcinoma can be difficult. Although previous studies have attempted to separate these tumors with various immunohistochemical panels, those series have been limited by small numbers of patients as well as the inclusion of benign sweat gland tumors.
  
  
  METHODS
  In this analysis, stains for p63, CK5/6, and D2-40 were included, as well as GATA3 and mammaglobin, in an evaluation of 21 primary sweat gland carcinomas and 33 examples of cutaneous metastatic breast carcinoma.
  
  
  RESULTS
  Immunoreactivity for p63, CK5/6, D2-40, GATA3, and mammaglobin was respectively observed in 81%, 71%, 52%, 71%, and 5% of sweat gland carcinomas compared with 6%, 6%, 6%, 91%, and 45% of metastatic breast carcinomas. These differences were statistically significant for p63, CK5/6, and D2-40. For the diagnosis of metastatic breast carcinoma, GATA3 was the most sensitive marker (91%), but its sensitivity was substantially lower. Mammaglobin was 95% specific for breast carcinoma but again suffered from limited sensitivity (45%) in this context.
  
  
  CONCLUSIONS
  These data suggest that p63 and CK5/6 are specific determinants for sweat gland carcinoma in the stated setting. In the absence of those analytes, metastatic breast carcinoma cannot always be identified to the exclusion of a primary tumor. This diagnostic scenario continues to require the procurement of a detailed clinical history regarding the number and duration of skin lesions in any given case.
authors.affiliation: From the Division of Surgical Pathology and Cytopathology, University of Virginia Medical Center, Charlottesville.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Mentrikoski
authors.affiliation: From the Division of Surgical Pathology and Cytopathology, University of Virginia Medical Center, Charlottesville. mrwick1@usa.net.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Wick
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000473:pathology*; D002277:Carcinoma / Q000473:pathology / Q000556:secondary*; D003710:Demography; D003937:Diagnosis, Differential; D004502:Education, Medical, Continuing; D005260:Female; D050990:GATA3 Transcription Factor / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D060785:Mammaglobin A / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D008875:Middle Aged; D012878:Skin Neoplasms / Q000473:pathology / Q000556:secondary*; D013544:Sweat Gland Neoplasms / Q000473:pathology*; D013545:Sweat Glands / Q000473:pathology; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; C081876:CKAP4 protein, human; D050990:GATA3 Transcription Factor; C494749:GATA3 protein, human; D060785:Mammaglobin A; D008565:Membrane Proteins
keywords: Differential diagnosis; Immunohistochemistry; Metastatic cutaneous breast carcinoma; Sweat gland carcinoma