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SEER Inquiry System - Report
Produced: 12/19/2025 12:50 AM
Question 20240027
Inquiry Details
References:
#1: Solid Tumor Rules. Malignant CNS, 2024 Update
#2: WHO Class CNS Tumors, 19-27; 39-55. 5th edition
Question:
Solid Tumor Rules/Multiple Primaries--Brain and CNS: How many primaries are accessioned when a 2005 diagnosis of glioblastoma multiforme is followed by a 2024 diagnosis of astrocytoma, IDH-mutant, WHO grade 4? See Discussion.
Discussion:
The patient underwent a gross total resection of the 2005 glioblastoma multiforme (9440/3). The patient was subsequently diagnosed with a 2024 diagnosis of astrocytoma, IDH-mutant, WHO grade 4 (9445/3).
Should Rule M13 apply to the new 2024 diagnosis and a new primary be accessioned because astrocytoma, IDH-mutant, WHO grade 4 is listed on a different row than glioblastoma? It is unclear whether histology 9445 should be classified as being on a different row because it is also listed as a subtype/variant for glioblastoma in Table 3. Table 3 lists histology 9445 as both “Astrocytoma, IDH-mutant, WHO grade 4” and as “Glioblastoma IDH-mutant.”
Answer:
Abstract two primaries using the 2024 Malignant Central Nervous System (CNS) and Peripheral Nerves Solid Tumor Rules, Rule M13. Glioblastoma, IDH-wild-type (9440/3) and astrocytoma, IDH-mutant, grade 4 (9445/3) are on two separate rows in Table 3 of the Malignant CNS and Peripheral Nerves Solid Tumor Rules.
WHO Classification of Central Nervous System, 5th edition, lists the subtypes of glioblastoma, IDH-wild-type as giant cell glioblastoma; gliosarcoma; and epithelioid glioblastoma. The term glioblastoma multiforme is not recommended for glioblastoma, IDH-wildtype in the 5th edition, and lists astrocytoma, IDH-mutant, grade 4 as a subtype of astrocytoma, IDH-mutant.
