Neurosarcoidosis Masquerading as Giant Cell Arteritis With Incidental Meningioma.

ABSTRACT: We present a case of vision loss secondary to neurosarcoidosis, which initially presented with severe bilateral vision loss, temporal headaches, and elevated erythrocyte sedimentation rate, concerning for giant cell arteritis. However, temporal artery biopsy was negative. Initial neuroimaging features were misinterpreted to represent a meningioma that did not account for his clinical presentation. Clinical course, including atypically rapid enlargement of presumed meningioma, development of skin lesions, appearance of optic nerve enhancement on MRI, and steroid response, strongly increased suspicion for sarcoidosis. Biopsy of a skin lesion demonstrated noncaseating granulomatous inflammation, consistent with sarcoidosis.