Pediatric Pleomorphic Xanthoastrocytomas: A Multicenter Neuroradiologic and Clinical Correlation Study

Pleomorphic xanthoastrocytomas (PXAs) are rare pediatric brain tumors accounting for approximately 1% of primary brain neoplasms in children and young adults. Despite recent imaging and molecular advances, gaps remain in our understanding of their diverse imaging characteristics and clinical outcomes. This study provides a large international, multi-institutional analysis of pediatric PXA, focusing on neuroimaging and clinical outcomes.

We conducted a retrospective international multicenter study including 63 pediatric patients with histologically confirmed PXAs. Neuroimaging data were reviewed, and molecular analyses were recorded with emphasis on BRAF V600E mutations and CDKN2A/B deletions. Treatment modalities and clinical outcomes, including progression-free and overall survival, were analyzed using statistical survival models.

Of tumors, 73.3% were CNS World Health Organization (WHO) grade 2 and 26.7% were CNS WHO grade 3. The median age at diagnosis was 10.7 years (interquartile range, 6.9 years). CNS WHO grade 3 tumors were significantly larger at diagnosis, with a median volume of 87,920 mm³ compared with 14,925 mm³ for grade 2 tumors (P = .03). BRAF V600E mutations were identified in 78% of cases, and CDKN2A/B deletions in 93.5%. On MRI, PXAs typically appeared well defined, with cortical and leptomeningeal contact (86.0% and 56.4%, respectively), frequent cysts (59.6%), and intermediate diffusivity (mean ADC, 1005 × 10^-6 mm²/sec). CT showed that most tumors were isointense to gray matter (52.0%), with hydrocephalus more common in grade 3 tumors (71.4% versus 26.3%, P = .07). Gross total resection was achieved in 73.7% of cases and was associated with improved progression-free survival, independent of age at diagnosis and tumor grade (hazard ratio = 0.39; 95% CI, 0.16-0.96; P = .041). Larger tumor volume correlated with poorer survival outcomes (hazard ratio = 3.47; 95% CI, 0.83-14.4; P =.087), also independent of tumor grade and age at diagnosis. Tumor recurrence occurred in 44.8% of patients at 3 years. The estimated 3-year overall survival rate was 94.7%.

Pediatric PXAs exhibit distinct neuroimaging and molecular features correlating with prognosis. Integrated evaluation of radiologic and clinical features is critical to improve risk stratification and guide personalized therapeutic strategies in this rare tumor population.