INTRODUCTIONChoroid plexus cysts (CPCs) are rare, benign neuroepithelial cysts that can cause obstructive hydrocephalus, although most are asymptomatic. Symptomatic CPCs are uncommon, and hydrocephalus from these cysts, especially intermittent in nature, is rarely reported. Diagnosing CPC-induced intermittent hydrocephalus can be challenging due to the cysts' CSF-like content and thin walls, often requiring advanced MRI sequences for detection.CASE REPORTWe present the case of a previously healthy 6-month-old male who developed intermittent triventricular hydrocephalus, presenting with projectile vomiting, lethargy, a bulging fontanel, and limited upward gaze. CT imaging revealed ventricular enlargement, and MRI revealed a thin membrane and a suspected choroid plexus cyst located within the choroid plexus of the anterior roof of the third ventricle, which is consistent with the dynamic obstruction of cerebrospinal fluid flow. After initial symptom resolution, the patient experienced recurrence within 24 h. Bilateral neuroendoscopic surgery was performed, involving cyst fenestration, shrinkage, and preventive endoscopic third ventriculostomy (ETV). Pathology confirmed a choroid plexus cyst. Postoperative imaging showed resolution of hydrocephalus and disappearance of the cyst. At follow-ups over 18 months, the patient remained symptom-free with no recurrence.DISCUSSIONThis case highlights the challenges of diagnosing and managing intermittent hydrocephalus caused by a septated choroid plexus cyst. Neuroendoscopy offers a minimally invasive treatment for obstructive hydrocephalus, particularly with complex cystic lesions. Our case required a bilateral approach due to the cyst's septation, which posed unique surgical challenges. A literature review revealed similar favorable outcomes with endoscopic techniques, but our case stands out due to the rare presentation of a septated CPC.CONCLUSIONThis report demonstrates the effectiveness of bilateral neuroendoscopic surgery in managing intermittent hydrocephalus caused by a septated choroid plexus cyst. The case underscores the importance of individualized surgical strategies and advanced imaging techniques in managing complex cases of hydrocephalus.