Pediatric High-Grade Astrocytoma With Piloid Features: A Comprehensive Literature Review

Area of Science:

• Neuro-oncology
• Pediatric Pathology
• Molecular Diagnostics

Background:

• High-grade astrocytoma with piloid features (HGAP) is a newly classified CNS tumor (WHO 2021).
• While HGAP is more common in adults, pediatric cases are infrequent and not well-understood.
• This study focuses on the epidemiology, clinical presentation, and molecular characteristics of pediatric HGAP.

Purpose of the Study:

• To review the limited data on pediatric HGAP.
• To characterize the clinical and molecular features of this rare tumor in children.
• To compare pediatric HGAP with its adult counterpart.

Main Methods:

• A systematic literature review was conducted for studies published between 2018 and 2025.
• Included cases were confirmed HGAP in patients 18 years or younger, verified by methylation profiling.
• Data on demographics, tumor site, histology, molecular alterations, and treatment were extracted.

Main Results:

• Seventeen pediatric HGAP cases were identified.
• The median age was 15 years, with a 2:1 male predominance.
• Common molecular alterations included CDKN2A/B loss (75%), FGFR1 alterations (55.6%), and ATRX loss (45.5%).

Conclusions:

• No clear clinical or molecular distinctions were found between pediatric and adult HGAP.
• Pediatric HGAP may be an underdiagnosed entity within the glioma spectrum.
• Accurate diagnosis requires methylation profiling, and larger pediatric studies are essential for management and prognosis.