Co-occurrence of Pediatric-Type Diffuse High-Grade Gliomas with Arteriovenous Malformations:  Case Report and Literature Review

Background: Pediatric-type diffuse high-grade gliomas (pDHGG) are recognized as a distinct entity in the 2021 WHO Classification of Central Nervous System Tumors, characterized by specific molecular features. Their co-occurrence with cerebral arteriovenous malformations (AVMs) is exceptionally rare, presenting significant diagnostic and therapeutic challenges. Herein, we report a rare case of concurrent pediatric diffuse high-grade glioma (pDHGG, WHO grade IV, H3-wildtype and IDH-wildtype) and a Spetzler-Martin grade I arteriovenous malformation in a pediatric patient. Case presentation: A 14-year-old male presented with recurrent seizures and progressive consciousness disturbance. Clinical assessment and neuroimaging revealed a right frontal lobe tumor (2.2×2.3×2.0 cm) closely associated with a Spetzler-Martin grade I AVM. Following preoperative endovascular embolization, complete microsurgical resection of both the tumor and AVM was achieved. Histopathology and molecular analysis confirmed pediatric diffuse high-grade glioma (WHO grade IV, H3-wildtype, IDH-wildtype). Immunohistochemistry showed positive GFAP and Olig-2, with retained ATRX expression. The patient completed standard adjuvant chemoradiotherapy (60Gy in 30 fractions with concurrent temozolomide) and remained disease-free at the 24-month follow-up. Literature review identified 8 prior cases of concurrent glioma and AVMs, mostly in males (7/8), with 75% being high-grade glioblastomas (WHO grade IV) and various AVM grades (I-III), resulting in 50% mortality despite surgery. Conclusion: Our multimodal approach in this rare case of concurrent pDHGG and AVM achieved favorable disease-free survival, highlighting the importance of comprehensive vascular assessment, staged intervention, and molecular diagnosis in managing such complex dual pathologies.