keratoacanthoma


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  • Clinical

    • explosive growth, capable of spontaneous regression
    • associations: Muir-Torre syndrome (KA, sebaceous neoplasms)

  • Histology

    • crater, keratin filled
    • invasive
    • glassy red keratinocytes, mild atypia
    • lack acantholysis
    • other features
      • neutrophil microabscesses in epithelium
      • lichenoid inflammation +/- eosinophils, plasma cells
      • elastic fibers on periphery of lesion
      • early lesion center have follicles with pseudoepitheliomatous hyperplasia and hypergranulosis
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