Periaqueductal gliosis causing hydrocephalus in a patient with neurofibromatosis type 1.

We present a case of primary nontumoral aqueductal stenosis associated with neurofibromatosis type 1 (NF-1) in an asymptomatic 11-year-old boy. The diagnosis of hydrocephalus followed the finding of bilateral papilledema at an ocular assessment and the diagnosis of NF-1 was made during hospitalization for the papilledema. Periaqueductal gliosis was suspected on cerebral T2-weighted magnetic resonance imaging (MRI). We believe that the incidence of hydrocephalus due to nontumoral aqueductal stenosis has been underestimated in NF-1. We emphasize the importance of early diagnosis of NF-1 and prompt evaluation in order to recognize this complication. In this regard MRI scanning offers more diagnostic advantages over other investigations. Forty-seven previously described cases have been collected from the literature.