RESUMO
BACKGROUND: The term "Tolosa-Hunt syndrome" (THS) has been used to refer to painful ophthalmoplegia associated with nonspecific inflammation of the cavernous sinus and many processes can result in a similar clinical picture, including infectious, inflammatory and neoplastic diseases. Rosai-Dorfman disease (RDD) is a lymphoproliferative disorder that rarely affects the central nervous system. We report a case of isolated CNS Rosai-Dorfman disease involving the cavernous sinus and presenting as "Tolosa-Hunt syndrome". CASE PRESENTATION: Our patient presented with horizontal diplopia due to impairment of cranial nerves III, IV and VI and a stabbing/throbbing headache predominantly in the left temporal and periorbitary regions. There was a nonspecific enlargement of the left cavernous sinus on MRI and the patient had a dramatic response to steroids. Biopsy of a frontal meningeal lesion was compatible with RDD. CONCLUSIONS: We highlight the importance of including Rosai-Dorfman disease as a differential diagnosis in cavernous sinus syndrome and demonstrate a satisfactory long-term response to steroid treatment in this disease.