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SEER Inquiry System - Report
Produced: 03/21/2026 1:37 AM
Question 20190019
Inquiry Details
References:
#1: Solid Tumor Rules. Non-malignant CNS, January 2019
#2: Subject matter expert
Question:
Solid Tumor Rules 2018/Histology--Brain and CNS: How is histology coded for a single meningioma tumor when the histology is a meningioma comprised of multiple specific subtypes/variants? See Discussion.
Discussion:
Example: Patient has a left cerebral meningioma that is meningothelial meningioma (9531) and two right-sided cerebral meningiomas: one that is transitional meningioma (9537) and the other that is meningioma, transitional and angiomatous, WHO Grade I. If the histology for the mixed tumor is 9534 (angiomatous meningioma), then there are three primaries. If the histology is 9537 (transitional meningioma), then there are two primaries.
Per Table 6, angiomatous meningioma is 9534/0 and transitional meningioma is 9537/0. There is no mixed histology coding rule, or mixed histology meningioma code. There is also no default rule that would instruct registrars to code the numerically higher ICD-O code or to default to a meningioma (NOS) histology code.
Answer:
Code the histology for the meningioma, transitional and angiomatous, WHO Grade I to Meningioma, NOS (9530/0). Since a mixed meningioma ICD-O code has not been proposed by WHO, we consulted with our expert neuropathologist.
The other option is to follow back with the pathologist and code what they feel is the predominant type. A new histology rule for coding mixed meningiomas will be added in a future update of CNS rules.
