Microsurgical Anterior Transcallosal Resection of Colloid Cysts of the Third Ventricle.

Colloid cysts of the third ventricle are benign and rare lesions of the central nervous system. Although gross total resection is the standard treatment of these lesions, there are multiple surgical routes proposed and discussed in the literature. Similarly, the origin of these colloid cysts remains a topic of debate. Long-term outcomes of anterior transcallosal approach have been analyzed and compared with the recent meta-analyses published in the literature. Additionally, the origin of these cysts is explored using immunohistochemical analysis.Eighty operations on 76 patients by a single surgeon over 37 years have been studied and the long-term outcomes have been presented. Additionally, ependyma, choroid plexus, and colloid cyst specimen have been compared using immunohistological staining with cytokeratin, S100, and PAX-7.The long-term outcomes with comparison with the literature show that microsurgical gross total resection using anterior transcallosal approach is the ideal treatment over other modalities. Preoperative hydrocephalus is a strong indicator for the location of the colloid cyst within the anterior third ventricle and for the selection of transforaminal versus interforniceal approach. In pathological study, the clear staining with PAX-7 points to this pathology being a remnant of the paraphysis.