Posterior fossa arachnoid cysts in adults: Surgical strategy: Case series

INTRODUCTION AND AIM: The management of posterior fossa arachnoid cyst (PFAC) in adults is controversial. To review our cases and literature, propose a practically useful surgical strategy, which gives excellent long-term outcome in management of PFAC. MATERIALS AND METHODS: We analyzed our case records of 26 large intracranial arachnoid cysts in adults treated over 12 years. Of them, we had 7 patients with symptomatic PFAC. Reviewed the literature of 174 PFAC cases (1973–2012) and added 7 of our new cases with a follow-up ranging from 3 to 12 years. RESULTS: In 6 cases the PFAC was located in the midline. In the 7(th) case, it was located laterally in the cerebello-pontine (CP) angle. All patients were treated surgically. Excision of the cyst was performed in 5 of these cases. Among the two intra-fourth ventricular cysts, in both the cases cysto-peritoneal shunt was performed. Postoperative computed tomography/magnetic resonance imaging showed variable decrease in size of the cyst even though clinically all patients improved. We propose a surgical strategy for the management of these cases which would aid the surgeon in decision making. DISCUSSION: We observed that these PFACs can occur either in the midline within the fourth ventricle or retroclival region or extra-fourth ventricular region. It can also develop laterally in the CP angle or behind the cerebellum or as intracerebellar cyst. Importance of this is except for Midline Intra-fourth ventricular cyst/retroclival cyst, the rest all can be safely excised with excellent long term outcome. The treatment strategy for Midline Intra-fourth ventricular cyst/retroclival cyst can be either cysto-peritoneal shunt or endoscopic fenestration of the cyst.