PATH-32 - Concordance for CDKN2A/B loss and TERT mutation in WHO 2021 classification grade 3 meningiomas: a retrospective study

Friday, November 18, 2022

7:30 PM – 9:30 PM ET

Location: West/Central Hall

Poster Presenter(s)

Carlen A. Yuen, MD (she/her/hers)

Columbia University Medical Center
New York, United States

Author(s)

Peter C. Pan, MD

Columbia University
New York, United States
DT

Damian E. Teasley

Columbia University Medical Center
New York, United States
MM

Michael L. Miller, MD, PhD

Columbia University Medical Center
New York, United States
YS

Yu Sun, MD, Phd

Columbia University Medical Center
New York, United States
PC

Peter D. Canoll, MD, PhD

Columbia University
New York, United States
AJ

Adela Joanta-Gomez, MD, MS

Columbia University Irving Medical Center
New York, United States
AB

Alicia V. Bargo

Columbia University Medical Center
New York, United States
Fabio Iwamoto, MD

Columbia University Medical Center
New York, United States

Background: The new WHO 2021 classification included CDKN2A/B loss and TERT mutation as new criteria for Grade 3 meningiomas, but excluded H3K27me3 loss. Malignant behavior may be influenced by DNA methyltransferases (DNMT3A). SUFU mutations may carry a predisposition for multiple meningiomas.

Methods: In this retrospective study, 228 patients with Grade 2, Grade 3 or recurrent Grade 1 meningiomas with resections from 1990 to July 2021 at Columbia University Medical Center were assessed for recurrence, histologic features, and molecular alterations.

Results: Of 228 patients with meningiomas, 9 were recurrent Grade 1, 9 were Grade 1 transformed to Grade 2, 109 were non-recurrent Grade 2, 77 were recurrent Grade 2, 13 were transformed Grade 2 to Grade 3, and 5 were non-recurrent Grade 3 and 6 were recurrent Grade 3. Median follow-up was 42.0 months. Of the recurrent/transformed tumors, 89 were radiation-resistant. Average mitotic counts for non-recurrent Grade 2 vs. recurrent/transformed Grade 2 and non-recurrent Grade 3 vs. recurrent Grade 3 meningiomas were 4 vs. 5, 24 vs. 27 mitoses/10HPF, respectively. Of 36 meningiomas evaluated with NGS, the most common alterations was NF2 (20/36). CDKN2A/B was lost in 5 meningiomas, three with Grade 2 that transformed to Grade 3 and two with recurrent disease. TERT was mutant in 3/36, 2 of which were Grade 2 that transformed to Grade 3 meningiomas. H3K27M me3 was tested by IHC in 4 patients, 3 with retained staining, all of whom did not recur and 1 with loss of staining in a Grade 1 transformed to Grade 2. DNMT3A was found in 2 tumors, both radiation-induced. SUFU occurred in 3/16, one of each grade, all solitary.

Conclusion: In our limited cohort, we observed concordance with the new WHO 2021 criteria for Grade 3 meningiomas