Spontaneous resolution of a prepontine arachnoid cyst. Case report and review of the literature.

Prepontine arachnoid cysts are rare developmental anomalies that occur almost exclusively in children. The symptomatic child typically suffers from hydrocephalus, visual impairment, endocrine dysfunction and/or cranial neuropathies. Some cysts, however, are discovered incidentally upon prenatal or postnatal imaging for other indications. While there is little doubt that surgical treatment should be initiated to help the symptomatic child, appropriate therapy for the asymptomatic patient is unclear. Although arachnoid cysts are often managed conservatively using serial imaging, the consequences of injury to surrounding structures with prepontine cysts often lowers the threshold for intervention. The natural history of asymptomatic prepontine arachnoid cysts is unknown. It has been reported that some cysts enlarge and cause symptoms, whereas others are stable for years. This report describes an index case of spontaneous resolution of a prepontine arachnoid cyst in a female infant over a 5-year period.