Describe a unique clinical presentation of sarcoidosis as optic nerve granuloma without any systemic manifestations. 

Sarcoidosis, a systemic inflammatory disorder, often involves the eye, primarily as uveitis [1] About 1% of patients have optic nerve involvement [2] We present an unusual case of optic nerve granuloma occurring as the first manifestation of neuro-ocular sarcoidosis.

A 38-year-old healthy female presented with a painless decrease in vision in her right eye over the course of one month. Her best-corrected visual acuity was 20/70 in the right eye and 20/20 in the left eye. The right eye exam was significant for relative afferent pupillary defect. Fundus exam revealed "hyperemic fluffy white mass-like lesion of the right optic nerve head" with subretinal fluid and mild vitreous cells.Aqueous humor testing for toxacara was negative. Serum inflammatory markers were high but extensive serology for autoimmune, infectious, and demyelinating etiologies was negative. Magnetic resonance imaging (MRI) showed avid enhancement of the optic nerve head only but otherwise unremarkable. Whole body CT revealed diffuse adenopathy which on biopsy showed inflammatory cells and ruled out malignancy. Due to high suspicion of ocular sarcoidosis, she was treated with high doses of oral prednisone for several weeks followed by a steroid-sparing agent. She was comanaged with retinal specialists. Close follow-up with serial exams and optical coherence tomography after initiating steroids showed prompt improvement in the size of optic nerve head granuloma and associated subretinal fluid. Within five months of immunosuppressant treatment visual acuity returned to 20/20 OU and there was resolution of the optic disc edema, subretinal fluid, and retinal vasculitis.

Neuro-ophthalmic manifestations of sarcoidosis especially as optic nerve head granuloma are very rare. A high clinical suspicion for sarcoidosis and a multidisciplinary approach is the key to its management with a favorable prognosis.