Abstract
BACKGROUND: Patients with Li-Fraumeni syndrome (LFS) are at higher risk for multiple malignancies from germline TP53 mutations. Because of DNA repair deficiences, radiation-induced sarcoma (RIS) can occur with decreased latency and increased frequency. Cranial RIS has not yet been associated with LFS. Here the authors detail the first report of RIS following glioma treatment in 2 patients with LFS. OBSERVATIONS: Patient 1, a 35-year-old male with LFS, underwent maximal resection of a left frontotemporal WHO grade II astrocytoma, followed by 6 weeks of photon/temozolomide chemoradiation therapy. Four years later, he developed a pleomorphic sarcoma involving the dura, skull, and overlying soft tissue. Patient 2, a 44-year-old male with LFS, underwent maximal resection of a left insular WHO grade III astrocytoma, followed by proton/temozolomide chemoradiation therapy. Five years posttherapy, he developed osteosarcoma involving the dura, skull, and subgaleal soft tissue. Pathological analysis verified TP53 mutations in both patients. LESSONS: These cases represent the first definitive report of cranial RIS following glioma chemoradiation therapy in patients with LFS. The short latency and aggressive nature of these tumors at the irradiated site highlight the need for proactive follow-up in patients with LFS after chemoradiation therapy to screen for RIS and improve outcomes through timely intervention. https://thejns.org/doi/10.3171/CASE25588.