Endoscopic techniques are useful in treating a variety of intra-ventricular conditions including hydrocephalus and for tumor biopsy. Ventricles are the fluid filled spaces in the center of the brain; cerebrospinal fluid (CSF) is synthesized in the ventricular system and circulates from the inside to the outside of the brain through the ventricular network. Endoscopy allows for access to the ventricular system with minimal brain disruption. Biopsy of tumors localized within the ventricular system is facilitated by ventriculoscopy. A meaningful treatment plan may developed from this established tissue diagnosis.