CNS & pituitary tumors

• Family of neoplasms most likely derived from meningothelial cells of the arachnoid mater

Meningioma ICD-O
• Meningioma9530/0

Contributed by Jared T. Ahrendsen, M.D., Ph.D.

Contributed by Jared T. Ahrendsen, M.D., Ph.D. and Chunyu Cai, M.D., Ph.D.

An intracranial neoplasm (histology shown in image) is resected from the lateral convexity of a 65 year old woman. Which of the following molecular alterations, if present, is compatible with a CNS WHO grade 3 designation for this tumor type?

1. EGFR amplification
2. Germline NF2 mutation
3. IDH mutation
4. Monosomy 22
5. TERT promotor mutation

E. TERT promotor mutation. The neoplasm shown is consistent with meningioma. CNS WHO grade 3 can be applied to meningiomas with either TERT promotor mutation or CDKN2A/B homozygous deletion. EGFR amplification (A) is a feature of IDH wildtype glioblastoma, not meningioma. While patients with germline NF2 mutations (B) (neurofibromatosis type 2) often have multiple meningiomas, this is not sufficient for CNS WHO grade 3 designation. IDH mutations (C) are present in diffusely infiltrating astrocytomas and oligodendrogliomas, not meningiomas. While monosomy 22 (D) is the most common genetic abnormality encountered in meningiomas, it is not sufficient for CNS WHO grade 3 designation.

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Reference: WHO grading of meningiomas