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SEER Inquiry System - Report
Produced: 02/10/2026 6:19 AM
Question 20240008
Inquiry Details
References:
#1: Solid Tumor Rules, 139-142. Non-Malignant CNS, 2023 Update
#2: WHO Class CNS Tumors. 5th edition
Question:
Solid Tumor Rules/Histology--Brain and CNS: Should the term “diffuse” be added to Note 2 in the Non-Malignant Central Nervous System (CNS) Solid Tumor Rules, Table 6: Specific Histologies, NOS, and Subtypes/Variants, for the papillary glioneuronal tumor 9509/1? See Discussion.
Discussion:
Should Note 2 state, "Beginning with cases diagnosed 1/1/2023 forward, diffuse leptomeningeal glioneuronal tumor is coded 9509/3? See the Malignant CNS rules." Currently the Note only states, "leptomeningeal glioneuronal tumor," but the histology that changed behavior is listed in both Table 6, Column 1 (Non-Malignant CNS) and Table 3 (Malignant CNS) as, "Diffuse leptomeningeal glioneuronal tumor."
Answer:
The correct term is diffuse leptomeningeal glioneuronal tumor listed as a synonym in Column 2.
We will add the term diffuse in Note 2, Column 1 with the 2025 updates. In the meantime, you can add "diffuse" to your pdf version until the update is published.
