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Quadrigeminal cistern arachnoid cyst treated by endoscopic ventriculocystostomy through the trigonal region.

BACKGROUND
When symptomatic, quadrigeminal cistern arachnoid cysts (QCACs), comprising 5 to 10% of all intracranial arachnoid cysts, are treated by open fenestration or shunt placement and in recent decades by endoscopic techniques. We introduce a novel endoscopic technique that may be used for surgery of QCACs.


PATIENT
A 52-year-old woman with a known history of QCAC (treated twice previously by open procedures) presented with symptoms, signs, and radiologic indicators of shunt malfunction and cyst recollection. Because of high-riding pineal gland and distortion of anatomy that resulted from the last surgeries, and loss of a suitable visual angle, a satisfactory ventriculocystostomy was not possible through the third ventricle. Therefore, the cyst was approached by entering the trigonal region of the lateral ventricle, allowing to perform ventriculocystostomy.


RESULTS AND CONCLUSION
Postoperative imaging and follow-up visits proved this approach to be efficacious. This report, for the first time, introduces the so-called transtrigone lateral ventricle cystostomy as an alternative for cases of QCAC for which the ventriculocystostomy via the third ventricle is not suitable.