Table 1.

Histologic subtypes (preceded by ICD-O-3 codes) of the studied tumors

ICCC	Astrocytomas (n=4605)	Oligodendrogliomas (n=315)	Mixed and unspecified gliomas (n=1222)	Neuroepithelial glial tumors of uncertain origin (n=70)	Total (6212)
Tumor grade
I	9384/3: subependymal giant cell		9380/3: glioma,		2074
	astrocytoma, malignant (n=1)		malignant
	9421/3: pilocytic astrocytoma, malignant		(n=37)*
	(n=1819)		9382/3: mixed
	9380/3: glioma, malignant (n=4)*		glioma (n=11)*
	9400/3: ASTROCYTOMA, NOS (n=202)*
II	9410/3: protoplasmic astrocytoma (n=22)	9450/3:	9380/3: glioma,	9430/3:	1345
	9411/3: gemistocytic astrocytoma (n=17)	oligodendroglioma, NOS	malignant	astroblastoma
	9420/3: fibrillary astrocytoma (n=183)	(n=288)	(n=78)*	(n=62)
	9424/3: pleomorphic xanthoastrocytoma		9382/3: mixed
	(n=84)		glioma (n=49)*
	9380/3: glioma, malignant (n=4)*
	9400/3: ASTROCYTOMA, NOS (n=558)*
III	9401/3: astrocytoma, anaplastic (n=311)	9451/3:	9380/3: glioma,		485
	9400/3: ASTROCYTOMA, NOS (n=124)*	oligodendroglioma,	malignant
		anaplastic (n=25)	(n=12)*
			9382/3: mixed
			glioma (n=13)*
IV	9440/3: glioblastoma, NOS (n=404)	9460/3:	9380/3: glioma,	9381/3:	552
	9441/3: giant cell glioblastoma (n=24)	oligodendroblastoma	malignant	gliomatosis
	9442/3: gliosarcoma (n=7)	(n=1)*	(n=34)*	cerebri (n=1)*
	9380/3: glioma, malignant (n=1)*		9382/3: mixed
	9400/3: ASTROCYTOMA, NOS (n=56)*		glioma (n=24)*
Not graded	9380/3: glioma, malignant (n=179)	9460/3:	9380/3: glioma,	9381/3:	1756
	9400/3: ASTROCYTOMA, NOS (n=601)	oligodendroblastoma	malignant	gliomatosis
	9423/3: polar spongioblastoma (n=4) **	(n=1) **	(n=890)	cerebri (n=7)
			9382/3: mixed
			glioma (n=74)

ICCC, International Classification of Childhood Cancer, Third edition; NOS, not otherwise specified

^*SEER grade was used (available for 1209 tumors in the grade related row) for histologic subtypes not associated with specific grades

^**subtypes no longer recognized in the current WHO classification.