Quadrigeminal cistern arachnoid cyst: A series of 18 patients and a review of literature.

BACKGROUND: Arachnoid cysts account for 1% of intracranial mass lesions. Quadrigeminal cistern arachnoid cysts are even rarer lesions. We report 18 cases of quadrigeminal cistern arachnoid cysts treated at our institute from 2002 to 2012. METHODS: We retrospectively analysed 18 patients with quadrigeminal cistern arachnoid cyst for clinical presentation, demographic profile, management and outcome. The age of the patients ranged from 29 days to 50 years (mean 17 years). The cysts were classified into 3 subtypes based on MRI findings. Surgical intervention was carried out in all the patients. RESULTS: Two patients had Type 1 cysts, 4 had Type 2 cysts and 12 had Type 3 cysts. Two patients (Type 1) underwent endoscopic third ventriculostomy (alone). Craniotomy and cyst wall excision along with ventriculocystostomy and cystocisternostomy were done in 4 patients with Type 2 cysts, and endoscopic fenestration of cysts to the sub-arachnoid space or the ventricles and endoscopic third ventriculostomy were done in 7 patients with Type 3 cysts. Two patients with Type 3 cysts underwent only endoscopic ventriculocystostomy and cystocisternostomy without endoscopic third ventriculostomy, while three patients underwent ventriculoperitoneal shunt. The follow- up period ranged from 6 months to 48 months (mean 23.7 ± 12.3 months). CONCLUSION: Quadrigeminal plate arachnoid cysts are generally symptomatic and require some form of surgical intervention. We believe that endoscopic fenestration of the cyst with cystocisternostomy or cystoventriculostomy, when combined with third ventriculostomy, is the procedure of choice for such patients. We do not recommend the placement of a ventriculoperitnoeal shunt alone. Operative re-exploration should be planned only after obtaining proper clinico-radiological correlation and not on the basis of imaging findings alone, as sometimes the cysts fail to regress but the symptoms improve.