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SEER Inquiry System - Report
Produced: 09/20/2025 2:37 AM
Question 20091122
Inquiry Details
References:
#1: 2007 SEER Manual, C-927. Appendix C
#2: WHO Class CNS Tumors, 53
Question:
MP/H Rules/Multiple primaries-Brain: Does a glioblastoma multiforme following a low grade glioma (oligodendroglioma) represent a new primary? See Discussion.
Discussion:
In 2/08 patient underwent resection of tumor of right frontal lobe. Path diagnosis showed a low grade glioma, favor low grade oligodendroglioma (WHO grade II). In 02/09 biopsy of a left thalamic mass showed glioblastoma mutiforme. Per rule M6 glioblastoma multiforme following a glial tumor is a single primary. Per path diagnosis, the first tumor represented a low grade glioma. However, oligodendroglioma is not on the glial branch of chart 1 in the MP/H rules.
Answer:
For cases diagnosed 2007 or later, glioblastoma multiforme following oligodendroglioma are multiple primaries according to rule M8. Rule M6 does not apply. M6 applies only to glial tumors as listed in chart 1. Chart 1 is based on the WHO classification. The WHO classification separates oligodendroglial tumors from glial tumors.
Cancer Site Category:
Brain and CNS
Data Item Category:
N/A
Other Category:
Multiple primaries
Year:
2009
