We present the case of a 35-year-old patient suffering from nasal obstruction and headache for 3 years. The patient was hospitalized for a recent and progressive decline of vision of the right eye associated with afferent pupillary deficit and inferior altitudinal hemianopsia. He was diagnosed with systemic sarcoidosis involving the central nervous system as illustrated by magnetic resonance imaging (MRI) scans showing different type diffuse lesions of meningo-encephalitis. Our case is characterized by severe cerebral pachyleptomeningeal lesions complicated by optic nerve compression and cervical spinal cord damage. MRI value of diagnosis for systemic neurosarcoidosis was supported by histological examination of a biopsy of the sphenoid sinus lesions that showed epithelioid granulomas presence without caseous necrosis. Thus, MRI of the brain and spinal cord is a powerful tool method in monitoring and diagnosing aymptomatic and symptomatic neurosarcoïodosis. MRI is also a powerful tool in monitoring the neurosarcoidosis during therapeutic treatments.