Rupture of arachnoid cysts is extremely rare. We herein report 2 cases of ruptured middle-fossa cysts with endoscopic treatment and review 30 previously published cases. Two pediatric male patients had a middle-fossa cyst accompanied by ipsilateral subdural effusion. Both patients had a tear in the outer membrane of the cyst detected by endoscopy. The tear was enlarged and fenestration of the medial wall was performed under endoscopy. Short-term postoperative imaging showed no obvious remission of the cyst or subdural effusion, and both patients had a satisfactory outcome in the short-term follow-up. The literature review revealed that middle-fossa arachnoid cysts were the most frequent type of cyst among the 30 cases, and 22 of all 27 middle-fossa arachnoid cysts were Galassi types II and III. We believe that large-volume middle-fossa arachnoid cysts tend to rupture secondary to an increase in pressure within the cyst caused by trauma and other factors that increase the intracranial pressure. Endoscopy is an effective and minimally invasive method for ruptured middle-fossa arachnoid cysts accompanied by subdural effusion. We advocate adequate communication among the cyst, subdural space, and cistern to achieve the best outcome. © 2014 Wolters Kluwer Health, Inc. All rights reserved.