Primary Spinal Epidural CIC-DUX4 Undifferentiated Sarcoma in a Child

Area of Science:

• Oncology
• Genetics
• Pathology

Background:

• CIC-DUX4 gene fusion defines a subset of Ewing-like sarcomas, typically found in soft tissues.
• Primary epidural spinal sarcomas are rare, and CIC-DUX4 positivity has not been previously reported in this location.

Observation:

• A 15-year-old girl presented with a T5-T6 epidural tumor with atypical plasmacytoid/rhabdoid morphology.
• Initial diagnosis was supported by WT-1 positivity and confirmed by fluorescent in situ hybridization (FISH) for CIC-DUX4 fusion.

Findings:

• Genomic profiling revealed breakpoints in CIC exon 20 and DUX4 exon 1, confirming the CIC-DUX4 fusion.
• Recurrent tumor showed increased pleomorphism and therapy-related cellular changes.
• The tumor exhibited aggressive behavior with intracranial progression and a fatal outcome.

Implications:

• This case expands the known spectrum of CIC-DUX4 sarcomas to include the epidural spine.
• The unusual morphology highlights diagnostic challenges and the need for molecular confirmation.
• Understanding treatment response and progression patterns is crucial for managing this rare entity.