[Adult-onset aqueductal stenosis caused by membranous occlusion in the aqueduct: a case report].

The authors report a case of adult-onset aqueductal stenosis caused by membranous occlusion of the aqueduct. The patient was a 35-year-old man, who suffered from progressive headache. On admission, computed tomography (CT) scan showed marked dilatations of the lateral and third ventricles. Midsagittal T1-weighted magnetic resonance imaging (MRI) scan showed a membranous occlusion at the lower end of the aqueduct, with dilatation of the proximal aqueduct and elevation of the tectum. Midsagittal cine-MRI demonstrated the cerebrospinal fluid flow in the aqueduct. The patient was diagnosed as having hydrocephalus resulting from membranous stenosis of the aqueduct by MRI. A ventriculo-peritoneal shunt operation was performed and his symptoms improved markedly. The membranous occlusion of the aqueduct is a rare cause of hydrocephalus. The etiology and therapy of aqueductal stenosis are discussed.