Long-term control of grade 3 intracranial solitary fibrous tumor achieved with pazopanib and stereotactic radiotherapy: illustrative case

BACKGROUND: Intracranial solitary fibrous tumors (SFTs) are rare mesenchymal neoplasms that often recur and metastasize. No standard therapy exists for patients with multiple extracranial metastases. OBSERVATIONS: A 56-year-old man with a left cerebellopontine angle tumor initially treated with Gamma Knife radiosurgery (GKRS) later underwent subtotal resection, confirming WHO grade 2 SFT. Despite repeated GKRS, he developed multiple intracranial and extracranial metastases; subsequent histopathological analysis confirmed progression to grade 3. Pazopanib was initiated for rapidly progressive bone and visceral disease and maintained at 200-400 mg daily. Marked responses were observed in lung, liver, and pancreatic metastases, with reduced development of new bone metastasis, requiring fewer stereotactic body radiotherapy courses. Intracranial disease progressed, necessitating two additional GKRS sessions. The patient survived 26 months after pazopanib initiation and approximately 8 years from diagnosis. LESSONS: Pazopanib demonstrates site-dependent efficacy in metastatic CNS SFT, with marked response in visceral metastases and reduced progression of bone metastases; however, a limited effect on intracranial disease is observed, requiring continued stereotactic irradiation. Flexible dosing enables sustained treatment. Long-term surveillance remains essential, as metastases may develop years after initial local control. https://thejns.org/doi/10.3171/CASE2656.