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.^3-5 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.