Recurrent Papillary Glioneuronal Tumor.

Area of Science:

• Neuro-oncology
• Neurosurgery
• Molecular Pathology

Background:

• Papillary glioneuronal tumors (PGNTs) are rare WHO grade I neoplasms.
• PGNTs typically exhibit a benign clinical course and respond well to surgical resection.
• However, rare instances of aggressive PGNTs with distinct clinical and histologic features have been reported.

Observation:

• A 67-year-old woman presented with a 3-year history of seizures and a frontoparietal mass.
• Histologic diagnosis post-subtotal resection was PGNT.
• The patient experienced disease recurrence within a year, progressing despite re-resection, radiation, and temozolomide therapy.

Findings:

• Molecular testing revealed a TERT promoter mutation, an FGFR3-TACC3 oncogenic fusion, and CDKN2A/CDKN2B copy number loss.
• These molecular alterations may correlate with the aggressive behavior observed in this case.
• The combination of TERT promoter mutation, FGFR3-TACC3 fusion, and CDKN2A/CDKN2B loss suggests a potential driver mechanism for aggressive PGNT.

Implications:

• This case highlights that PGNTs, while generally benign, can exhibit rare aggressive behavior and recurrence.
• Comprehensive molecular profiling of PGNTs is crucial for identifying aggressive subtypes.
• Identifying specific molecular alterations may pave the way for targeted therapies and improved treatment strategies for aggressive PGNTs.