Progressively worsening headache due to arachnoid cyst in a teenager: a case report

Abstract

Headache is one of the most common neurological complaints in the pediatric population and encompasses a broad differential diagnosis. Although primary headache disorders constitute the majority of cases, secondary etiologies—including intracranial space-occupying lesions—must be considered, particularly in patients with persistent, progressive, or treatment-refractory symptoms. Arachnoid cysts are benign, cerebrospinal fluid (CSF)-filled, extra-axial lesions that are typically congenital in origin and arise from developmental abnormalities of the arachnoid membrane. While most arachnoid cysts are asymptomatic and incidentally detected, symptomatic cases may present with chronic headache due to mass effect or impaired CSF circulation. They account for less than 1% of intracranial space-occupying lesions. Case Presentation: We report the case of a young female patient with long-standing, treatment-resistant headache without focal neurological deficits. Neuroimaging revealed an intracranial arachnoid cyst exerting mass effect consistent with increased intracranial pressure. Given the persistence of symptoms despite conservative management, surgical intervention was undertaken. The patient underwent cystoperitoneal shunt placement. Postoperative follow-up demonstrated marked clinical improvement with substantial reduction in headache severity and frequency. Radiological evaluation confirmed a significant decrease in cyst size and alleviation of mass effect. This case underscores the importance of comprehensive evaluation for secondary causes in pediatric patients presenting with refractory headache. Although arachnoid cysts are frequently incidental findings, symptomatic lesions may require surgical management. Cystoperitoneal shunting can provide favorable clinical and radiological outcomes in appropriately selected patients. Early recognition and timely intervention are essential to prevent prolonged morbidity.