Derived Grade

NAACCR Item

NAACCR #1975
Code Description
1

G1: Tumor with areas of retinoma [retinocytoma] (fleurettes or neuronal differentiation)

2

G2: Tumor with many rosettes (Flexner-Wintersteiner or Homer Wright)

3

G3: Tumor with occasional rosettes (Flexner-Wintersteiner or Homer Wright)

4

G4: Tumor with poorly differentiated cells without rosettes and/or with extensive areas (more than half of tumor) of anaplasia

A

Well differentiated

B

Moderately differentiated

C

Poorly differentiated

D

Undifferentiated, anaplastic

9

Grade cannot be assessed (GX); Unknown