The authors present the case of a 63-year-old woman with a history of bilateral hearing loss and progressive and profound bilateral vision loss. After extensive testing but no diagnosis, biopsy of the left optic nerve showed non-necrotizing granulomatous inflammation with giant cells consistent with sarcoidosis. This was a diagnostically challenging case because of its unusual presentation as an isolated bilateral progressive optic neuropathy with no systemic or other ocular manifestations. This case reminds us that neurosarcoidosis should always be in the differential diagnosis of a bilateral optic neuropathy because of its variability of presentation and potential for visual recovery with treatment.
At the time of initial vision loss, the patient had a swollen right optic disc. Two weeks later, bilateral optic disc swelling was noted. While the initial brain and orbital MRI was interpreted as showing no abnormalities, a repeat MRI nine months later showed marked bilateral optic nerve enhancement. The patient was treated with high-dose corticosteroids but did not improve.
She was then referred to the authors' university ophthalmology department. At that time, visual acuity was light perception in the right eye and no light perception in the left eye. Color vision was absent in the right eye. The patient was treated with another course of systemic steroids but her vision did not improve.
A repeat MRI performed nine months after initial vision loss demonstrated mild optic nerve enlargement and marked enhancement bilaterally, extending from the orbital portions of the optic nerves to the optic chiasm. The third MRI of the brain and orbits showed progression of involvement of the optic nerves and chiasm with an increase in the asymmetric enlargement of the optic nerves, with the left greater than the right. There was uniform enhancement throughout the cross-sectional area of the nerves, thickening and enhancement of the pituitary stalk and bilateral asymmetric enhancement of the oculomotor and trigeminal nerves, as well as the facial and vestibulocochlearcranial nerve complexes in the internal auditory canals.
The authors then performed a biopsy of the left optic nerve in an attempt to obtain a definitive diagnosis for the cause of the patient's bilateral optic neuropathy. The biopsy showed numerous, well-formed, non-necrotizing granulomas associated with a marked chronic inflammatory infiltrate composed of lymphocytes and plasma cells. Scattered multinucleated giant cells were seen in the granulomas. The diagnosis of sarcoidosis was then made.
The patient was treated with intravenous cyclophosphamide but did not respond and was switched to methotrexate. However, the authors report that her condition worsened, and she became completely deaf and blind.
The authors conclude that the diagnosis of neurosarcoidosis can be quite challenging because of the diverse range of its clinical features. They say that although MRI is sensitive, it is nonspecific. However, they say that optic nerves in which inflammation or infiltration is a prominent feature typically show perineural enhancement and thickening, findings that are especially useful in cases with a negative systemic workup. They say that in such cases, like this one, an optic nerve biopsy may be required to establish a diagnosis.