Epileptic Seizures Associated with an Arachnoid Cyst in an Unusual Anatomical Location: A Case Report

Introduction: Intracranial arachnoid cysts are developmental malformations of the arachnoid membrane characterized by the presence of cerebrospinal fluid within a cystic cavity lined by arachnoid cells. These lesions are thought to result from abnormal embryological development of the leptomeninges and represent approximately 1% of all intracranial lesions. Although they can occur throughout the cranial cavity, a predilection for the middle cranial fossa has been consistently reported. The widespread use of modern neuroimaging techniques has led to an increased rate of incidental diagnosis, as the majority of arachnoid cysts remain asymptomatic throughout life. Nevertheless, symptomatic lesions may produce a broad spectrum of clinical manifestations related to local compression of adjacent neural structures. Seizures constitute a frequent presenting symptom, reported in up to one-third of symptomatic cases, and may occur in association with focal neurological deficits, neurocognitive impairment, headaches, or features of intracranial hypertension. The relationship between arachnoid cysts and epilepsy remains incompletely understood, particularly in cases involving rare anatomical locations, where diagnosis and management continue to be subjects of ongoing debate.
Case description: We present the case of a 26-year-old male patient with no prior history of cranial trauma, congenital anomalies, developmental disorders, intracranial infections, or neurosurgical procedures, who presented with a one-month history of generalized seizures accompanied by headaches and vomiting. Neurological examination revealed no focal deficits. Neurophysiological assessment suggested a right frontal epileptogenic focus, consistent with imaging findings demonstrating a right frontal arachnoid cyst on CT and MRI. Considering the close radiological and electroclinical correlation, microsurgical cyst fenestration with cyst volume reduction was performed. The postoperative course was marked by a gradual decrease in seizure frequency, followed by complete seizure remission. This observation supports the role of microsurgical decompression as a safe and effective treatment strategy for symptomatic arachnoid cysts associated with epilepsy, offering excellent seizure control and favorable long-term outcomes.
Conclusion: When appropriately indicated, surgical treatment of arachnoid cysts can provide complete seizure remission and favorable postoperative outcomes.