[Multiple gliomas].

Area of Science:

• Neuro-oncology
• Molecular Pathology
• Cancer Genomics

Background:

• Glioblastoma (GBM) is a highly aggressive primary brain tumor.
• Accurate classification of glial tumors is crucial for prognosis and treatment.
• Genetic alterations play a key role in tumor development and classification.

Observation:

• Case 1: A patient presented with multifocal, synchronous, wild-type IDH1/2 glioblastoma (RTK1 subtype) exhibiting specific chromosomal anomalies (chr7 duplication, chr10 deletion, homozygous CDKN2A deletion).
• Case 2: A second patient's tumor presentation was diagnostically complex, posing challenges in classification.
• The second case could represent either a rare instance of metachronous, multicentric gliomas (including IDH1-mutant, 1p/19q-codeleted oligodendroglioma WHO grade 2 and RTK2-glioblastoma) or secondary glioblastoma.

Findings:

• The first patient's tumor displayed a distinct molecular profile consistent with a specific glioblastoma subtype.
• The second patient's case highlights the diagnostic difficulties in differentiating complex glial tumor presentations.
• The potential for secondary glioblastoma development after radiotherapy for oligodendroglioma was considered.

Implications:

• These cases underscore the importance of integrated diagnostics, combining histopathology and molecular profiling for accurate brain tumor classification.
• Understanding rare and complex glial tumor subtypes can refine diagnostic criteria and therapeutic strategies.
• Further research is needed to elucidate the mechanisms underlying the development of such complex and rare brain tumors.