Rare presentation of hydrocephalus occlusus caused by membranous obstruction of the foramina of Magendie and Luschka: a case report.

Fourth ventricle outlet obstruction is a rare cause of obstructive hydrocephalus in children. Although surgical management has been reported, the diagnostic challenges, differential considerations, and therapeutic strategies remain debated. We report a 5-year-old boy with progressive vomiting, severe headache, gait instability, and incontinence. High-resolution magnetic resonance imaging with T2-CISS sequences confirmed a membranous obstruction at the foramina of Magendie and Luschka. The patient underwent microsurgical fenestration via suboccipital craniotomy, with histopathological confirmation of arachnoid membranes without signs of infection or malignancy. The postoperative course was favorable with complete symptom resolution. Notably, persistent papilledema was observed at 2-month follow-up despite clinical improvement, but showed gradual regression during subsequent visits, underlining the need for cautious postoperative monitoring.