Resection of Massive "Tarry" Intra/Extra-ventricular Prepontine Colloid Cyst: 2-Dimensional Operative Video.

Colloid cysts are typically slow-growing lesions that account for approximately 1% of primary intracranial neoplasms and predominantly exist intraventricularly. These benign lesions typically can exist symptom-free for years and do not require surgical intervention. However, if the location of the colloid cyst is symptomatic, surgical debulking may be indicated. In this intraoperative video, we illustrate the case of an 8 cm, intra/extra-ventricular colloid cyst that appeared as a craniopharyngioma on preoperative imaging, but upon resection via a trans-middle temporal gyrus approach, was found to be very atypically filled with a thick, "tarry" substance, which we hypothesize is due to serial, subacute lesional hemorrhages. After debulking and piecemeal resection of the majority of the mass with ultrasonic aspiration and microsurgical tools, a hard, calcified nodule was left tenaciously adherent to the superior cerebellar artery to prevent damage to this vascular structure.