Grade 4 astrocytoma vs. grade 4 glioblastoma: is there any clue in H&E?

Objective: Gliomas are the most common primary tumors of the central nervous system. The fifth edition of the World Health Organization (WHO) Classification of Tumors of the CNS identifies IDH mutant astrocytomas grade 4 and IDH wild type glioblastomas grade 4 as distinct entities. This study aimed to identify morphological indicators that could predict IDH mutation status in grade 4 diffuse astrocytomas and grade 4 glioblastomas among fifty patients from two groups.

Methods: Hematoxylin and eosin (H&E)-stained tumor slides were scanned using a digital scanner and further histopathological examinations were performed on digital images, with additional calculations and measurements.

Results: The study showed that, IDH-wildtype glioblastomas and IDH-mutant grade 4 astrocytomas exhibit unique morphological features, particularly in relation to levels of necrosis, microvessel density, and the presence of "C" or "Ring" shape giant cells.

Conclusion: Despite advancements in genomic biomarker technology, histology remains an essential tool for predicting patient outcomes. Therefore, pathologists must continue to investigate and document the morphological implications of molecular changes in CNS tumors.