Surgical navigation-assisted endoscopic biopsy is feasible for safe and reliable diagnosis of unresectable solid brain tumors.

Stereotactic biopsy has been validated for tissue sampling of deep-seated lesions that cannot be easily resected via open craniotomy. However, some inherent problems including the inability to directly observe the lesion and difficulty in confirming hemostasis limit its usefulness. To overcome these issues, we used the endoscope in brain tumor biopsy, for not only intraventricular tumors but also intraparenchymal tumors. The rigid scope was used in association with a surgical navigation system for intraparenchymal lesions via a transcortical route. There were no useful anatomical landmarks when the trajectory to the lesions was decided; therefore, surgical navigation system was required for the transcortical procedures. The endoscopic procedure described here was attempted in 21 cases of intraparenchymal lesions between January 2007 and February 2012. A definitive diagnosis was obtained in all cases, and genetic analysis was performed when required. Serious postsurgical hemorrhage or neurological deficits were not observed in any cases. Endoscopic surgery provides a clear view of the target and makes it easier to differentiate tumor tissue from normal brain tissue. Moreover, the endoscope helped to confirm hemostasis during the procedure. Thus, endoscopic biopsy has the potential to contribute toward safe and reliable diagnosis of brain tumors.