Quadrigeminal Cistern Epidermoid Cyst: Neuroendoscopy and Endoscope-Assisted Supracerebellar Infratentorial Approach

The pineal region is a complex anatomical location with multiple surrounding important neurovascular structures. 1 , 2 Several approaches to this region have been described, including posterior interhemispheric, transchoroidal, infratentorial supracerebellar, supracerebellar and infracerebellar trans-sinus, and their modifications. Neuroendoscopy and endoscope-assisted surgery have been widely applied to aid resection of pineal region lesions. 3 , 4 , 5 A 40-year-old man presented with tonic-clonic seizures and bilateral papillary edema on fundus examination. Computed tomography showed a midline lesion at the level of the quadrigeminal cistern with mass effect on the aqueduct of Sylvius and posterior wall of the third ventricle, triggering obstructive triventricular hydrocephalus. As a first intervention, a third ventriculostomy was attempted unsuccessfully owing to unfavorable third ventricle floor anatomy. This approach was used to obtain a biopsy specimen, which showed an epidermoid cyst. Ventriculoscopy showed a communication of the pineal recess and quadrigeminal cistern owing to tumor invasion. An external ventricular drain was placed to control the hydrocephalus until complete resection was performed ( Video 1 ). Several days later, tumor resection was carried out via the median supracerebellar infratentorial approach with the patient in semisitting position. After near-total resection under microscope, the third ventricle and both lateral recesses were explored with the endoscope. A small tumor remnant (visible only with endoscope) was identified and removed. This step was essential to achieve complete resection, confirmed by magnetic resonance imaging. The patient was discharged 6 days later without complications. During follow-up, the patient remains asymptomatic. The combination of microneurosurgery, neuroendoscopy, and endoscope-assisted surgery improves management of pineal region lesions and facilitates complete resection.