Extracranial Frontal Arachnoid Cyst in an Adult Patient: Case Report

Arachnoid cysts are a relatively common finding in the general population. Primary arachnoid cysts are congenital malformations and are commonly intracranial cysts. Secondary arachnoid cysts develop as a result of an osseous defect and inadequate dural closure. Intradiploic arachnoid cysts are rare lesions of the skull that are typically seen in posttraumatic cases. Extracranial arachnoid cysts, when suspected, should be studied thoroughly on imaging, and they should be explored beyond the extracranial compartment to provide permanent treatment of this problem. The dura should be explored even if the underlying bone looks intact because if not explored and a possible rent is not treated, the extracranial cyst has the potential to recur. To the best of our knowledge, this type of unusual pathology has not been reported earlier. We hereby report a case of successfully treated recurrent extracranial arachnoid cyst in an adult patient.