St. Anne-Mayo grading system of astrocytomas

Last revised by Assoc Prof Frank Gaillard on 26 Sep 2021

The St. Anne-Mayo grading system, also known as the Daumas-Duport grading system, introduced in 1988 was for a time a popular system for grading diffuse astrocytomas but has now been replaced by the WHO grading system which, however, was derived from the St Anne-Mayo system and thus shares many similarities 1-3

The St. Anne-Mayo grading system is a 4 tiered system and uses the presence of 4 morphologic criteria to assign a grade: 

  1. nuclear atypia
  2. mitosis
  3. endothelial proliferation - 'piled-up' endothelial cells. NOT hypervascularity
  4. necrosis

The grade then depends on the accumulation of these criteria as follows: 

  • grade 1: 0 criteria
  • grade 2: 1 criterion (usually nuclear atypia)
  • grade 3: 2 criteria (usually nuclear atypia and mitosis)
  • grade 4: 3 or 4 criteria

Note that, unlike the WHO classifications up to and including the revised 4th edition (2016) that used Roman numerals, the St. Anne-Mayo system used Arabic numerals. This has been adopted by the 5th edition of the WHO classification (2021) 5

History and etymology 

Named after Catherine Daumas-Duport, a French pathologist 2 from Sainte Anne hospital who also worked together with the Mayo-Clinic in the United States 4.

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