Reversal of Symptomatic Tumoral Narcolepsy, With Normalization of CSF Hypocretin Level

Narcolepsy is primarily characterized by excessive daytime sleepiness (EDS) and cataplexy.1 Most patients with sporadic narcolepsy with cataplexy and HLA DQB1*0602 have low CSF hypocretin-1 level in relation to a loss of hypocretin neurons.1–3 The origin of hypocretin neurons deficiency remains uncertain, but an autoimmune process is the most probable.1–3 Symptomatic narcolepsies associated with tumors located in the hypothalamic or the brainstem regions have been previously reported, half of them with cataplexy.4 The nature of the link among clinical symptoms, sleep onset REM periods, HLA, and CSF hypocretin remains unclear, especially in symptomatic narcolepsy. However, due to widespread excitatory projections to monoaminergic and cholinergic neurons, hypocretin neurons are supposed to be involved in maintaining wakefulness. Undetectable CSF hypocretin levels that correspond to a major functional impairment of the hypocretin region predispose to hypersomnia.1–3 We report a patient with severe symptomatic narcolepsy caused by a primary CNS lymphoma with undetectable CSF hypocretin-1 level whose symptoms reversed after chemotherapy. ### Case report. A 46-year-old man was referred to our …