Neurosarcoïdose cérébrale

We report the case of a 37-year old patient with right optic neuropathy. Magnetic resonance imaging (MRI) showed T2 hypersignal in the midline, enhanced after gadolinium injection (figure 1). Cerebrospinal fluid (CSF) analysis revealed lymphocytic meningitis with 64 white blood cells associated with hyperproteinorachy. Chest CT scan suggested the diagnosis of granulomatous inflammation, namely Stage 2 sarcoidosis. The level of serum angiotensin-converting enzyme (ACE) was high. The patient underwent corticosteroid therapy with good outcome. Sarcoidosis is a granulomatous diffuse, multisystemic disorder of unknown etiology. Neurologic sarcoidosis occurs in 5-15% of cases and neurologic symptoms suggest it in 10-30% of cases. Meningoencephalitis and cranial nerve involvement are the most common cliniconeurological manifestations, that are very varied. Facial nerve is the most common nerve to be affected, followed by the optic nerve. Brain MRI can better identify brain lesions, manifesting as infiltrating nodules in T1-weighted hyposignal and in T2-weighted hypersignal enhanced after contrast injection. It mainly affects the suprasellar region with involvement of the hypothalamus, the pituitary peduncle and the optic chiasm. Other anomalies are easily identified by gadolinium contrast agent, including diffuse or nodular thickening of the leptomeninges manifesting as pachymeningitis and lesions in the brain parenchyma (parietal, frontal, cerebellar regions) or in the spinal cord. The diagnosis is based on combination of clinical, radiological, laboratory tests and on histological data. Treatment is based on corticotherapy as first-line therapy sometimes associated with immunosuppressants.