RESUMO
INTRODUCTION: We present an infant with an expansive posterior fossa arachnoid cyst and severe clinical deterioration due to decompensated obstructive hydrocephalus. Given the dilated Sylvius aqueduct, we favoured the endoscopic transfrontal transaqueductal route to approach the cyst. CASE REPORT: A 12-month-old boy was acutely admitted for severe symptoms of intracranial hypertension. Imaging revealed spacious cystic formation in the posterior fossa with expansive behaviour towards the brain stem, fourth ventricle and cerebellum associated with obstructive triventricular hydrocephalus. The patient underwent electromagnetically navigated transfrontal transaqueductal cyst fenestration with simultaneous ETV from two precoronal trajectories with a rigid endoscope. CONCLUSION: A transaqueductal approach with a rigid endoscope is rarely published, and we were amazed by the impact on the child's clinical improvement after this minimally invasive endoscopic procedure. The case is well documented with imaging and perioperative neuroendoscopic views.
