Possible mechanism of secondary narcolepsy with a long sleep time following surgery for craniopharyngioma.

A 19-year-old woman suffered from severe excessive daytime sleepiness accompanied with long sleep episodes both in the daytime and nighttime and frequent episodes of cataplexy shortly after the removal of craniopharyngioma in the intrasellar space. Multiple sleep latency test showed a typical finding of narcolepsy, and cerebrospinal fluid orexin concentration was below the narcolepsy cut-off value. MRI-tractography showed a clear lack of neuronal fiber connections from the hypothalamus to the frontal lobe. SPECT using (123)I-IMP showed frontal hypoperfusion. These connection damages could have been responsible for the occurrence of narcolepsy-like symptoms and long daytime sleep episodes in this case.