A rare case of isolated metastatic disease in a young woman with papillary thyroid carcinoma and a novel method for diagnosis: illustrative case

Despite the rarity of brain metastases in pediatric and young adult populations with DTC, especially in the absence of concurrent extracranial disease, this case highlights the importance of thorough neurological evaluation and consideration of CSF thyroglobulin as a potential marker. This case emphasizes the need for vigilance in surveillance and an alternative to brain biopsy when intracranial metastasis is suspected. https://thejns.org/doi/10.3171/CASE25386.