Endoscopic approach and stereotactic radiosurgery for a posterior third ventricular Central Neurocytoma – case report and literature review

INTRODUCTION: Central Neurocytomas (CN) are a rare intracranial tumour, most often arising in the lateral ventricles and presenting with obstructive hydrocephalus. Isolated lesions in the third ventricle are uncommon. We present the fourth reported case of posterior third ventricular CN successfully managed surgically via endoscopy, allowing for concurrent biopsy and therapeutic endoscopic third ventriculostomy (ETV). Stereotactic radiosurgery was administered for the residual lesion. A brief review of CNs and previous similar cases is also provided. PRESENTATION OF CASE: A 58-year-old male presented with progressive decline in cognition and gait. Subsequent Magnetic Resonance Imaging revealed obstructive hydrocephalus secondary to a posterior third ventricular lesion. An endoscopic biopsy and concurrent cerebrospinal fluid diversion by ETV was performed. Pathological analysis was consistent with a CN with positivity to Synaptophysin. MIB-1 proliferation index was 1%. There was good clinical recovery, and the patient underwent adjuvant stereotactic radiosurgery 1.5 months post-surgery. DISCUSSION: Due to the rarity of CNs arising from the third ventricle, there are only three previous reports of these approached endoscopically. Such a technique allows for good visualisation of the lesion, and therapeutic ETV to relieve obstructive hydrocephalus. This case supports this approach as a valid, minimally invasive option. Additionally, this is the first case to report the MIB-1 proliferation index, contributing to future outcome evaluation of endoscopic approaches to typical (MIB-1 < = 2%) verses atypical (MIB-1 > 2%) CNs. CONCLUSION: Endoscopic biopsy with concurrent ETV and adjuvant stereotactic radiosurgery is a valid treatment option for deep seated isolated small posterior third ventricular CNs.