Exceptional Long-term Survival in BRAF V600E-mutant Anaplastic Pleomorphic Xanthoastrocytoma: A Case Report with 12-year Disease-free Follow-up

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Anaplastic pleomorphic xanthoastrocytoma (APXA) is a rare World Health Organization (WHO) grade 3 glial neoplasm with limited long-term survival data.While grade 2 pleomorphic xanthoastrocytoma (PXA) demonstrates favorable 5-year overall survival rates of 80-90%, anaplastic variants carry a significantly worse prognosis with 5-year survival of approximately 55-57%.BRAF V600E mutations are detected in 50-78% of PXAs and have been associated with improved clinical outcomes; however, cases with follow-up exceeding 10 years are exceptionally rare in the literature, making long-term prognostic assessment challenging.We report an exceptional case of BRAF V600E-mutant APXA with 12-year diseasefree survival following gross total resection and comprehensive multimodal adjuvant therapy.A 30-year-old woman presented in October 2014 with a generalized tonic-clonic seizure.Magnetic resonance imaging (MRI) revealed a 32×27 mm contrast-enhancing mass in the left temporal lobe.The patient underwent left temporal craniotomy with gross total resection.Histopathological examination demonstrated pleomorphic tumor cells with bizarre hyperchromatic nuclei, multinucleated giant cells, rhabdoid and spindle-shaped morphology, and lipid-laden xanthomatous cells with eosinophilic cytoplasm.Immunohistochemistry showed glial fibrillary acidic protein and S-100 positivity, Ki-67 proliferation index of 15%, and 13 mitoses per 10 high-power fields.BRAF V600E mutation was confirmed by molecular analysis, and the tumor was diagnosed as PXA, WHO grade III.The patient was lost to follow-up after the first surgery.Eight months postoperatively, the patient presented with tumor recurrence following another seizure, and second surgery achieved gross total resection.Upon histopathological re-evaluation, findings were consistent with APXA recurrence rather than malignant transformation.Ten days after the second surgery, adjuvant treatment was initiated with dynamic arc radiotherapy delivering a total dose of 6000 centigray, concurrent temozolomide 75 mg/m 2 , followed by six cycles of adjuvant temozolomide 150 mg/m 2 .Follow-up cranial MRI scans performed at regular intervals over the subsequent 12 years consistently demonstrated stable postsurgical changes without any evidence of tumor recurrence.At 12-year follow-up, the patient remains clinically stable and disease-free.This case demonstrates that exceptional long-term survival exceeding 12 years is achievable in BRAF V600E-mutant APXA with gross total resection and comprehensive multimodal adjuvant therapy.The BRAF V600E mutation may serve as a favorable prognostic biomarker and represents a potential therapeutic target.This case underscores the importance of molecular profiling for accurate prognostication and identification of targeted therapeutic options in this rare tumor entity.

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