Cytological features of diffuse and circumscribed gliomas

Area of Science:

• Neuropathology
• Cytopathology
• Oncology

Background:

• The World Health Organization (WHO) classification of gliomas integrates morphological, genetic, and molecular data.
• Intraoperative diagnosis of gliomas requires rapid assessment, often relying on cytological evaluation.
• Current intraoperative methods cannot assess genetic or molecular profiles.

Purpose of the Study:

• To present essential cytological features of gliomas for intraoperative analysis.
• To emphasize the diagnostic challenges and recognition of specific glioma subtypes during surgery.
• To review newly described paediatric-type diffuse gliomas and circumscribed astrocytic gliomas.

Main Methods:

• Review of cytological features relevant to intraoperative glioma diagnosis.
• Focus on distinguishing neoplastic tissue in low-grade gliomas.
• Identification of characteristic cytology for various glioma subtypes, including IDH-mutant and IDH-wildtype glioblastomas.

Main Results:

• The primary challenge in intraoperative diagnosis of astrocytoma IDH-mutant, grade 2 is identifying neoplastic tissue.
• High-grade gliomas are often diagnosed collectively due to limitations in intraoperative genetic/histological assessment.
• Specific cytological findings are noted for oligodendroglioma, IDH-mutant and 1p/19q-codeleted, and various glioblastoma subtypes.

Conclusions:

• Intraoperative cytological recognition of glioma subtypes remains critical despite evolving classifications.
• Pathologists must identify circumscribed astrocytic gliomas, which often exhibit low-grade features with atypical morphology.
• Further cytological reports are needed for recently described paediatric-type diffuse gliomas.