Photodynamic therapy for recurrent spinal diffuse midline glioma with a modest extension of overall survival: illustrative case.

BACKGROUND: Diffuse midline glioma (DMG), a highly malignant CNS tumor, is classified as a World Health Organization grade 4 tumor. Its overall survival prognosis, even after standard treatment, is typically extremely poor. Photodynamic therapy (PDT) represents an innovative treatment modality with promising results for intracranial malignant gliomas. However, its use for spinal malignant gliomas has not yet been explored, despite their pathological similarity to intracranial malignant gliomas. OBSERVATIONS: The present case of a 28-year-old female patient with recurrent spinal DMG represents the first documented report concerning the effects of PDT on spinal malignant gliomas, with the pathological postmortem findings. Despite the successful application of PDT to the resection cavity of the spinal DMG, cervical spinal cord edema developed soon after surgery. The blood flow to the spinal cord parenchyma was thought to be altered but reversible. The patient's overall survival was 21 months after the initial surgery. LESSONS: This case highlights the potential of PDT as a feasible and promising adjunctive treatment for spinal malignant gliomas. The observed clinical course and pathological findings may provide valuable insights for future research and therapeutic development. https://thejns.org/doi/10.3171/CASE25751.