Cholesterol granuloma of the sphenoid wing with long-term growth dynamics: illustrative case.

backgroundCholesterol granulomas typically arise in the petrous apex of the temporal bone, and involvement of the sphenoid wing has not been reported. This case is notable not only for its rare sphenoid wing origin but also for the ability to document its growth dynamics over long-term imaging follow-up. OBSERVATIONS: A 35-year-old man was found to have a mass along the lateral aspect of the left sphenoid wing during evaluation after minor head trauma. Long-term radiological follow-up demonstrated gradual enlargement of the lesion, prompting resection. Histopathological examination revealed cholesterol clefts surrounded by granulomatous tissue, consistent with a diagnosis of cholesterol granuloma originating from the sphenoid wing. LESSONS: Although cholesterol granulomas most often occur in pneumatized regions of the skull base, particularly the petrous apex, this lesion developed in an area without bone aeration. Together with the documented long-term growth dynamics, this case suggests that cholesterol granulomas can develop independently of bone pneumatization and highlights the importance of considering alternative pathogenic mechanisms, supported by unique long-term radiological documentation of lesion growth. https://thejns.org/doi/10.3171/CASE26724.