A difficult diagnostic case of secondary trigeminal neuralgia caused by idiopathic orbital inflammation

Abstract

We report a difficult diagnostic case of secondary trigeminal neuralgia due to idiopathic orbital inflammation. A 65-year-old man presented right facial pain in the first division area of the trigeminal nerve. Along with increasing facial pain, right eye pain and diplopia appeared. Ophthalmalgia was cured with steroid eye drops, but facial pain and diplopia persisted. CT findings revealed a mass in the right ethmoid sinus and orbit with bone destruction. These findings suspected malignant sinus disease and surgery was performed. Histologic examination showed no evidence of atypical cells, granulomas, or fungi, just infiltrations of inflammatory cells. Despite postoperative treatment with antibiotics for sinusitis, facial pain and diplopia suddenly worsened. The possibility of idiopathic orbital inflammation emerged. After starting oral prednisolone, symptoms promptly improved. In this case, many atypical findings made the diagnosis difficult. Idiopathic orbital inflammation has been reported to rarely involve the paranasal sinuses and should be considered as a differential diagnosis.