Intracranial arachnoid cyst complicated with subdural hygroma in a 10-year-old child: A case report and literature review

Arachnoid cysts are abnormal collections of fluids within the arachnoid membrane after a doubling of the structure. These benign lesions represent only 1% of all intracranial space-occupying lesions. The affected patient can remain asymptomatic for several years, which is an incidental finding in most cases. Cysts have been reported to rupture after a minor head trauma, causing subdural hygroma or hematoma; however, spontaneous rupture complicated with subdural hygroma has been rarely reported. Herein, we report a rare case of a 10-year-old boy whose pregnancy follow-up, delivery, and parent’s medical history were unremarkable. The patient was admitted for a temporal arachnoid cyst complicated with subdural hygroma, which was determined to be caused by intracranial hypertensive syndrome. He was successfully treated through endoscopic arachnoid cyst fenestration, wherein a pathway was created for the cyst to communicate with the subarachnoid space through the basal cisterns. The choice of treatment for arachnoid cysts remains controversial. Endoscopic treatment is considered when an ipsilateral subdural hygroma is present. Intracranial hypertensive syndrome subsided immediately after surgery. No post-operative complications occurred. The child recovered uneventfully in the post-operative period and was discharged 5 days after surgery. He underwent a follow-up computed tomography 1 month later, confirming a progressive regression of the hygroma as well as arachnoid cyst.