St. Anne-Mayo grading system of astrocytomas

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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grading system, introduced in 1988 was for a time a popular system for grading diffuse astrocytomas but has now largely been replaced by the WHO grading system which is, however, derived from the St Anne-Mayo system and thus shares many similarities .

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

  • nuclear atypia
  • mitosis
  • endothelial proliferation - 'piled-up' endothelial cells. NOT hypervascularity
  • 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 classification, Roman numerals are NOT usually used.

    History and etymology 

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