WHO grading
Also written as: WHO — World Health Organization grading
World Health Organization classification system for brain tumors based on histological features and molecular markers.
Full Definition
WHO grading is the internationally accepted system for classifying central nervous system tumors according to their histological appearance, biological behavior, and increasingly, molecular characteristics. The system assigns grades I through IV, with Grade I representing benign, slow-growing tumors and Grade IV indicating highly malignant, rapidly proliferating neoplasms. The 2021 WHO classification incorporates molecular features alongside traditional histology, fundamentally changing diagnostic criteria for many tumor types and requiring integrated diagnosis combining morphology with genetic alterations.
Usage
Usage note: Always specify the WHO edition year when citing classification criteria.
In Context
- "The tumor was classified as WHO Grade II based on integrated histological and molecular findings." — Brain tumor pathology report
- "WHO grading has evolved significantly with the incorporation of molecular markers in the 2021 update." — Pathology conference presentation