Optic Perineuritis As a Presenting Sign of Sarcoidosis

Purpose: To report a rare case of optic perineuritis as the presenting sign of sarcoidosis. Case summary: A 57-year-old man presented with decreased visual acuity and pain with extraocular movement in his left eye starting 2 weeks earlier. He had a history of asymptomatic optic perineuritis in that eye 18 months previously, which had improved after 1 month on oral prednisolone. His best corrected visual acuity had decreased to 20/50 and he also had relative afferent pupillary defect and color vision defects in the left eye. Slit lamp examination results were normal. There were no inflammatory reactions in the anterior chamber or vitreous. Fundoscopy showed optic disc edema. Orbital magnetic resonance imaging showed diffuse enhancement surrounding the left optic nerve. The serum levels of eosinophil cationic protein and angiotensin-converting enzyme were markedly increased. A chest radiograph showed bilateral hilar lymph node enlargement. A biopsy via endobronchial ultrasound-guided transbronchial needle aspiration revealed multifocal non-caseating granulomas. Acid fast bacilli stain showed no evidence of tuberculosis. Based on these findings, he was diagnosed with sarcoidosis. After treatment with high-dose intravenous methylprednisolone and subsequent tapering with oral prednisolone for 6 months, the visual acuity improved. Conclusions: Optic perineuritis can be the initial sign of sarcoidosis. Therefore, sarcoidosis should be considered in the differential diagnosis of optic perineuritis.