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SEER Inquiry System - Report
Produced: 02/01/2026 7:41 AM
Question 20250018
Inquiry Details
References:
#1: Solid Tumor Rules. 5th edition, Non-malignant CNS, 2025 Update
#2: WHO Class CNS Tumors, online version. 5th edition
Question:
Solid Tumor Rules/Histology/Behavior--Brain and CNS: How are histology and behavior coded when the Integrated Diagnosis is "Meningioma, WHO Grade 2," and the Histological Classification is "Meningioma with elevated mitotic activity, hypercellularity, necrosis, and sheeting architecture?" See Discussion.
Discussion:
We are increasingly seeing pathologists use this terminology to describe WHO G2 meningiomas, but the histology term "Atypical meningioma" is not being used, and a more specific "Histological Classification" of other WHO Grade 2 meningiomas (i.e., chordoid or clear cell meningioma) is not given. Can the combination of meningioma, WHO Grade 2 plus the histological classification listing multiple features of an atypical meningioma be used to code morphology to 9539/1? Or is this just a meningioma, NOS 9530/0 despite the WHO Grade 2 classification?
Answer:
Code meningioma, NOS (9530/0) based on the integrated diagnosis and histological classification. WHO Classification of Central Nervous System Tumors, 5th edition, states that brain invasion is a criterion for the diagnosis of CNS WHO grade 2 meningioma, and there is no statement of brain invasion, atypical meningioma, or other WHO grade 2 lesions. WHO has not proposed behavior codes based on WHO grade alone.
