Transformation of Pleomorphic Xanthoastrocytoma with Germline ATM Mutation into a SMARCB1-Deficient Rhabdoid Tumor: A Case Report
10.15264/cpho.2026.33.1.34
- Author:
Hyeonseung LEE
1
;
Hyun Jin PARK
;
Bo Kyung KIM
;
Kyung Taek HONG
;
Hyoung Jin KANG
;
Sung-Hye PARK
;
Ji Hoon PHI
;
June-Young KOH
;
Jung Yoon CHOI
Author Information
1. Department of Pediatrics, Seoul National University Children’s Hospital, Seoul National University College of Medicine, Seoul, Korea
- Publication Type:CASE REPORT
- From:Clinical Pediatric Hematology-Oncology
2026;33(1):34-38
- CountryRepublic of Korea
- Language:English
-
Abstract:
Secondary rhabdoid tumors (RTs) with atypical teratoid/rhabdoid tumor-like features rarely arise from, or coexist with, pleomorphic xanthoastrocytomas (PXAs), and their clinicopathological and molecular characteristics remain poorly understood. We report a 17-year-old girl with a temporal lobe mass that, upon gross total resection, pathologically contained both RT and PXA components. Immunohistochemistry revealed loss of INI1 expression restricted to the RT component, while the PXA area retained INI1. Next-generation sequencing identified a shared BRAF::TRIM24 fusion and homozygous deletion of CDKN2A/2B in both components, indicating a shared clonal origin. Additionally, a germline ATM frameshift mutation (c.5288_5289insGA) was identified in both tumor components, making the first such report in central nervous system tumors. SMARCB1 loss was confined to the RT component, further supporting the hypotheses of clonal evolution and secondary transformation. Despite gross total resection, craniospinal irradiation, and chemotherapy, the patient developed rapid leptomeningeal dissemination and died 5 months after surgery. This case provides clinicopathological and molecular evidence for clonal evolution and secondary transformation of PXA into an RT. The presence of germline ATM mutation may have therapeutic and biological relevance. Further studies are required to clarify the pathogenesis and optimal management of these rare and aggressive tumors.
