2026 Proffered Presentations
S047: COHORT ANALYSIS OF RADIATION-INDUCED MENINGIOMAS REVEALS SELECTIVE VULNERABILITY AND ANATOMICAL PREDILECTIONS
Gabrielle Luiselli, MD; Eduardo Maury, MD, PhD; Ruchit Patel; Varun Bhave; Samuel Emerson, MD, PhD; Erickson Torio, MD; Joseph Driver, MD; Scott Ryall, PhD; Azra Ligon, PhD; Rifaquat Rahman, MD; Elizabeth Claus, MD, PhD; David Meredith, MD, PhD; Sandro Santagata, MD, PhD; Wenya Linda Bi, MD, PhD; Mass General Brigham
Introduction: Radiation-induced meningiomas (RIMs) are a late complication of cranial irradiation, often arising decades after treatment for pediatric malignancies. Compared with sporadic meningiomas, RIMs are more frequently multifocal, recurrent, and exhibit higher histopathologic grade. However, their genomic profile and anatomic distribution relative to prior radiation fields remains incompletely understood. We aimed to explore the spatial and genomic features of RIMs to guide future surveillance and management strategies.
Methods: We performed retrospective analysis of 68 radiation-induced meningiomas from 60 patients treated at the Brigham and Women’s Hospital (BWH) between 2008-2025. Clinical history, tumor location, radiation strategy, treatment dates, and original histopathological grade were extracted from the medical record. Histopathology was reviewed by board-certified neuropathologists and graded per World Health Organization (WHO) Classification of Tumors. Anatomic location of 52 meningiomas with available MRIs was assessed by volumetric contouring of pre-operative MRIs using 3D Slicer. Whole genome chromosomal analyses were performed using microarrays to derive copy-number profiles.
Results: Radiation-induced meningiomas exhibited supratentorial predilection even in patients who received focal radiation boost to the posterior fossa. Among the 16 patients who received targeted radiation, either alone or as a boost to whole brain radiation therapy (WBRT), the incidence of frontal meningiomas was similar to those who received WBRT alone (40%), despite the posterior fossa being the most frequent boost target. Of the 14 patients who received whole craniospinal radiation, none developed spinal meningiomas. 38.6% of patients had multiple RIMs at diagnosis, which increased to 58.3% at time of last follow-up. Radiographic meningiomatosis was noted in 19.3% of patients.
When compared to 761 sporadic meningiomas, RIMs showed a higher proportion of aggressive features including high copy number alternation (CNA) burden (>4/sample, OR = 3.1, 95% CI: 1.9–5.3, p<0.0001). Several CNAs were enriched in RIMs compared to sporadic cases, including chromosomal arm losses in 1p, 6q, and 18q. Even RIMs with less than 3 mitoses, a histopathologic marker of less aggressive disease, 77% harbored 1p loss, with 6q and chromosome 22/NF2 deletions present in 26% and 77% respectively, highlighting a discrepancy between relatively bland histology and molecular profiles suggestive of higher aggressiveness.
Conclusions: Volumetric imaging demonstrated an enrichment of radiation-induced meningiomas in the supratentorial compartment, even among patients who received posterior fossa irradiation. Notably, spinal meningiomas are rare following craniospinal irradiation. These observations suggest selective vulnerability within the central nervous system despite diffuse radiation exposure, potentially reflecting biologic heterogeneity of meningeal cells as determined by their embryologic origins. In addition, the enrichment of chromosomal alterat?ions in RIMs with deceptively bland histopathology underscores the need to further investigate their distinct biologic underpinnings.
Figure1. A.Volumetric analysis of radiation-induced meningiomas (RIMs). Color scale indicates tumor counts. B.Similar spatial distribution stratified by WHO grade 1 (low grade), and WHO grade 2/3 (high grade)
.jpg)
Figure2. A.Oncoprint of copy number alterations (CNAs) across chromosomal regions in 68 RIM samples. Each column represents an individual tumor. B.Oncoprint of CNAs in RIMs with less than 3 mitoses