Tolosa-Hunt syndrome is characterized by painful ophthalmoplegia due to a granulomatous inflammation in the cavernous sinus. Corticosteroid therapy dramatically resolves both clinical and radiological findings. We report a case of a patient 55 years old, initially managed as cavernous sinus thrombophlebitis, and by means of magnetic resonance imaging studies, was then diagnosed as Tolosa-Hunt syndrome. After receiving adequate therapy, clinical symptoms improved. We recommend serial magnetic resonance imaging studies when Tolosa-Hunt syndrome is suspected in order to differentiate it from other cavernous sinus lesions that can mimic it clinically and radiologically.