| 1 |
WHO Grade I: Circumscribed tumors of low proliferative potential associated with the possibility of cure following resection |
| 2 |
WHO Grade II: Infiltrative tumors with low proliferative potential with increased risk of recurrence |
| 3 |
WHO Grade III: Tumors with histologic evidence of malignancy, including nuclear atypia and mitotic activity, associated with an aggressive clinical course |
| 4 |
WHO Grade IV: Tumors that are cytologically malignant, mitotically active, and associated with rapid clinical progression and potential for dissemination |
| L |
Stated as "low grade" NOS |
| H |
Stated as "high grade" NOS |
| A |
Well differentiated |
| B |
Moderately differentiated |
| C |
Poorly differentiated |
| D |
Undifferentiated, anaplastic |
| 9 |
Grade cannot be assessed (GX); Unknown |
