An FGFR1-Altered Intramedullary Thoracic Tumor with Unusual Clinicopathological Features: A Case Report and Literature Review

Background: Primary spinal gliomas are rare in the pediatric population. Separately, FGFR1 genomic aberrations are also uncommon in spinal cord tumors. We report a case of a previously well adolescent who presented with progressive symptoms secondary to an intramedullary tumor with unique radiological and molecular characteristics. Case Presentation: A previously well 17-year-old male presented with worsening mid-back pain associated with lower limb long-tract signs. Magnetic resonance imaging (MRI) of his neuro-axis reported a long-segment intramedullary lesion with enhancing foci and a multi-septate syrinx containing hemorrhagic components from C4 to T12. The largest enhancement focus was centered at T7. Additional MRI sequences observed no intracranial involvement or vascular anomaly. He underwent an emergent laminoplasty and excision of the thoracic lesion. Intraoperative findings demonstrated a soft, grayish intramedullary tumor associated with extensive hematomyelia that had multiple septations. Active fenestration of the latter revealed blood products in various stages of resolution. Postoperatively, the patient recovered well, with neurological improvement. Final histology reported a circumscribed low-grade glial neoplasm. Further molecular interrogation via next-generation sequencing panels showed activating FGFR1 p.K656E and V561M missense alterations. The unique features of this case are presented and discussed in corroboration with a focused literature review. Conclusions: We highlight an interesting case of an intramedullary tumor with unusual radiological and pathological findings. Emphasis is on the importance of tissue sampling in corroboration with genomic investigations to guide clinical management.