A Case of Primary Intramedullary Infantile Fibrosarcoma With an RBPMS::NTRK3 Fusion and Response to Larotrectinib.
Mégane Le Quang, Julie Tandonnet, Nathalène Truffaux et al.
✦ AI-curated · Sources linked
Case in brief
A 4-week-old infant presented with rapidly progressive cervical myelopathy due to primary intramedullary infantile fibrosarcoma. Histological analysis revealed a spindle cell tumor with diffuse S100 and pan-TRK expression. RNA sequencing identified an RBPMS::NTRK3 fusion, and treatment with the TRK inhibitor larotrectinib resulted in significant clinical and radiological improvement within one month.
Diagnostic / clinical pearl
The identification of an RBPMS::NTRK3 fusion in infantile fibrosarcoma highlights the importance of molecular profiling in diagnosing and managing rare tumors.
Why it matters
This case demonstrates the potential effectiveness of TRK inhibitors like larotrectinib in treating primary central nervous system tumors with NTRK fusions.