Thoracolumbar Epidural Arachnoid Cyst of Difficult Clinical Management: Case Report

Abstract

Introduction: Among the primary lesions occupying the spinal space, only 1% corresponds to the epidural arachnoid cyst (EAC). This condition is usually asymptomatic, and identified accidentally in imaging tests. In symptomatic cases, total surgical resection is recommended. Objective: To describe a case of EAC refractory to clinical treatment. Methods: A 45-year-old woman had lumbar pain for six years and increased pain in the last months, with irradiation to the left lower limb (corresponding to L1). No other alterations found in the physical examination. Magnetic resonance imaging (MRI) of the spine revealed an intravertebral cystic lesion at T12-L1 level, in the left posterolateral position, causing enlargement of the foramen, and suggesting an epidural arachnoid cyst. Results: Due to failure of the initial clinical treatment, the patient underwent left T12-L1 hemilaminectomy, resection of the cyst and correction of dural failure. The patient progressed with effective pain control and MRI confirmed absence of residual lesion. Conclusion: EAC is more common in men (4:1) and may be congenital or acquired. The most common topography is thoracic (65%). Its clinical presentation is low back pain, lower limb pain and paresthesia. MRI is the method of choice for diagnosis and surgical intervention is restricted to cases that are symptomatic or refractory to clinical treatment, and the prognosis tends to be excellent. We conclude that, in addition to being a rare and commonly asymptomatic condition, an adequate therapeutic approach is essential for complete cure, avoiding intense pain and manifestations that bring about a drastic reduction of functional capacity. Level of evidence: IV. Type of study: Case series.