Abstract 12
Category: Clinical
At the end of the session, participants will be able to:
- Recognize the histological and molecular features of infant-type hemispheric glioma (IHG).
- Differentiate IHG from desmoplastic infantile astrocytoma /ganglioglioma.
- Differentiate IHG from other high-grade gliomas based on histological and molecular criteria.
COI Disclosure:
None to disclose.
Presenter
I am a neuropathologist and pediatric pathologist
Authors
Murad Alturkustani¹
1 Department of Pathology, King Abdulaziz University, Jeddah, Saudi Arabia
Target Audience:
CanMEDS:
Medical Expert (the integrating role)
Infant-type hemispheric glioma is mostly relatively well-demarcated tumor and not diffusely infiltrative
Abstract
Background: IHG has been identified as a distinct entity with unique methylation patterns and gene fusions, presenting a better prognosis than other pediatric high-grade gliomas. The current WHO classification presents discrepancies regarding the tumor’s circumscription, necessitating further investigation.
Methods: The Children’s Brain Tumor Network dataset of 1029 samples was accessed, selecting tumors from patients aged 0-4 years, resulting in 191 gliomas, glioneuronal tumors, and ependymomas. Methylation profiles were analyzed using the Heidelberg v12.5 and v12.8 classifiers. Cases were selected based on diagnoses of IHG, desmoplastic infantile astrocytoma /ganglioglioma (DIA/G), or high-grade gliomas with available methylation class. Morphological assessments focused on tumor circumscription, low-grade areas, glial differentiation, and high-grade features.
Results: The final cohort included 12 cases: 4 with an initial diagnosis of DIA/G, and 8 with an initial diagnosis of high-grade astrocytoma (6 diagnosed as IHG). All IHG cases were infantile tumors, while DIA/G cases were in older children. Both IHG and DIA/G were well-circumscribed, whereas the case with diffuse infiltration was classified as diffuse pediatric high-grade glioma. The 4 DIA/G cases were heterogeneous, with only one showing the methylation profile of DIG. One DIA/G case was reclassified as IHG. The remaining six IHG cases were initially diagnosed as high-grade astrocytoma.
Conclusion: IHG is predominantly a well-circumscribed tumor, contrasting with the diffuse infiltration characteristic of other pediatric high-grade gliomas. Recognizing these histological features, along with molecular profiling, is crucial for accurate diagnosis and management.