Modified Ringertz grading system for diffuse astrocytomas

Last revised by Frank Gaillard on 26 Sep 2021

The modified Ringertz grading system has historically been one of the more frequently used grading systems for diffuse astrocytomas, but has essentially been replaced by the WHO grading system.

Unlike the WHO grading system and St Anne-Mayo grading system (also known as the Dumas-Duport grading system) which divide astrocytomas into 4 grades, the Ringertz grading system only has 3 grades, and only applies to diffuse astrocytomas (i.e. not WHO grade 1 tumors such as pilocytic astrocytomas or subependymal giant cell astrocytomas) 1

As such, there is a rough equivalence between WHO 2 to 4 and modified Ringertz I - III, although there are some differences in the criteria required to fulfill various grades. 

The modified Ringertz grading system is as follows 2:

  • grade 1 = astrocytoma
    • roughly equivalent to WHO grade 2
    • mild hypercellularity
    • mild nuclear atypia (nuclear enlargement, hyperchromasia, pleomorphism) 
    • rare mitotic figures
  • grade 2 = anaplastic astrocytoma 
    • roughly equivalent to WHO grade 3
    • more cellular than grade 2
    • more nuclear atypia 
    • more mitotic figures
    • endothelial proliferation (note this is a WHO grade 4 feature)
  • grade 3 = glioblastoma
    • roughly equivalent to WHO grade 4
    • presence of geographic necrosis +/- surrounding pseudopalisading tumor cells

History and etymology

Nils Ringertz (1932-2002) a pathologist from Stockholm originally proposed the grading system in 1950 4

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