Staged Gamma Knife radiosurgery for multicompartment skull base metastatic ameloblastoma: illustrative case

BACKGROUND: Metastatic ameloblastoma with skull base or intracranial involvement is exceedingly rare, and optimal local therapy is not well defined when complete resection is infeasible or morbid. Stereotactic radiosurgery (SRS) may offer focal control for complex skull base targets. OBSERVATIONS: A patient with ameloblastoma underwent six prior resections at an outside institution (2010, 2011, 2015, 2018, 2021, and November 2024) before developing multicompartment skull base progression involving the cavernous sinus-sellar region and the infratemporal fossa-right lateral orbital region. SRS (Gamma Knife radiosurgery) was delivered in a staged (sequenced) manner to anatomically distinct targets over time, treating the cavernous sinus-sellar component in November 2024 and the recurrent lesion lateral to the right orbit in April 2025. The cavernous sinus-sellar target received 13 Gy (50% isodose), and the second target received 14 Gy (50% isodose). Follow-up imaging demonstrated marked volumetric response (-93% and -100%, respectively), with clinical improvement and no clinically identified adverse radiation effects. LESSONS: In selected patients with heavily pretreated metastatic ameloblastoma, staged SRS to different skull base compartments can provide durable local control while limiting morbidity. Radiosurgical sequencing may preserve future options in a longitudinal disease course and underscores the need for long-term imaging surveillance. https://thejns.org/doi/10.3171/CASE2651.