Introduction: Paediatric tumours in the sellar and parasellar regions present clinical and surgical challenges due to anatomical position and behaviour. We illustrate a rare case which caused obstructive hydrocephalus. Case Presentation: The study included a 14-year-old girl with a glioneuronal tumour (40 mm) originating from the optic chiasm, obliterating the aqueduct, with consequent triventricular hydrocephalus. The patient underwent extended endoscopic endonasal surgery and repair of the skull-base deficiency using a multi-layer technique with fascia lata. The 12-month follow-up showed no complications or recurrences, with recovery in visual acuity. Conclusion: The immediate placement of external ventricular drainage, in combination with an extended trans-sphenoidal approach, is a safe and feasible option to treat suprasellar paediatric lesions with hydrocephalus. [ABSTRACT FROM AUTHOR]