Froin Syndrome: Unmasking a Rare Case of Spinal Cord Gliosarcoma

Primary spinal gliosarcoma is a rare, high-grade central nervous system tumor with mutations in mesenchymal and glial lineages. We describe a rare case of a 61-year-old woman presenting with a new-onset, nonspecific headache, and seizures for 3 months. Despite negative brain imaging, cerebrospinal fluid sampling revealed xanthochromia and markedly elevated protein consistent with Froin syndrome, which implicated a lesion in the spinal cord. Subsequent anatomical and functional imaging of the spinal cord detected an encasing tumor that was later biopsy confirmed as a primary spinal gliosarcoma.