[Narcolepsy disclosing neurosarcoidosis].

A 37-year-old man developed excessive daytime sleepiness, sleep attacks and cataplexy revealing an hypothalamic tumour. Multiple Sleep Latency Tests (MSLT) were characteristics of narcolepsy. Tissue typing was positive for HLA DR2 and DQ1. Most cases of narcolepsy are idiopathic without any evidence of brain pathology. Although symptomatic narcolepsy may occur occasionally with diencephalic lesions. The relationship between narcolepsy with diencephalic lesions is unsettled and will be discussed.