Paget disease


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  • Clinical

    • breast (extension of intraductal carcinoma)
    • extramammary (extension of adenocarcinoma or de novo)
  • Histology

    • large clear cells
    • percolates epithelium (pagetoid spread), crushes basal layer, can penetrate stratum corneum
    • look for underlying adenocarcinoma
  • Stains

    • Paget cells positive: mucin, EMA, CEA, CK7, CAM5.2
      • mucin = MUC1, mucicarmine, Alcian blue, PASD resistant
    • HER2+
    • neg: S100
  • Ddx

    • Toker cell hyperplasia (HER2-, CEA-, mucin-)
    • melanoma (HMB45+, MART1+, S100+)
    • SCC (p63+)
    • BCC (BerEp4+)
    • intraepidermal porocarcinoma (focal ductal structures)