American Urological Association - Prostatic Adenocarcinoma: Gleason Grading (Modified Grading by ISUP)


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Prostatic Adenocarcinoma: Gleason Grading (Modified Grading by ISUP)

Image A

Image B

  • Based purely on architecture, classified into 5 patterns or grades (1 to 5) representing a spectrum from better-differentiated well-formed glands to poorly differentiated cancer incapable of forming glands.
  • After its development by Dr. Donald Gleason in 1966, underwent refinements in 1974 and 1977 (image A), and had its latest modification in 2005 by ISUP (image B).
  • Gleason Score (GS) = primary + secondary grades (scores of 2-10).
    • In prostatectomy:
      • Primary grade: most predominant pattern.
      • Secondary grade: second most predominant pattern.
      • In case there are 3 different grades, a tertiary pattern is included if it is higher than the secondary grade.
    • In biopsy:
      • Primary grade: most predominant.
      • Secondary grade: highest non-predominant pattern.
  • Examples:
    • Gleason 3 (60%) and Gleason 4 (40%).
      • In prostatectomy and biopsy: Gleason 3+4=7.
    • Gleason 3 (100%). (If pure, the only pattern present is doubled).
      • In prostatectomy and biopsy: Gleason 3+3=6.
    • Gleason 3 (60%), Gleason 4 (30%) and Gleason 5 (10%).
      • In prostatectomy: Gleason 3+4=7, with tertiary pattern 5.
      • In biopsy: Gleason 3+5=8.
  • In biopsy, GS is assigned to each separately designated prostate subsite.
  • ISUP 2005 modifications take into account grading of variants of prostate carcinoma and unusual morphologies, such as
    • Ductal adenocarcinoma, considered as Gleason grade 4 (GS 8 if pure).
    • Pseudohyperplastic variant, graded as Gleason score 3+3=6.
    • Mucinous fibroplasia is subtracted and gland graded (mostly Grade 3).