Uncommon and Unbelievable; Extradural Spinal Arachnoid Cyst: A Rare Case Report and Systematic Review of the Literatures

Introduction: Spinal arachnoid cysts are rare fluid-filled sacs that develop within the spine’s protective layer, known as the arachnoid membrane. These cysts were first described by British neurologist George Spiller in 1903. The arachnoid cyst gets its name from the arachnoid membrane, one of the three layers of the meninges that surround and protect the brain and spinal cord. This membrane is responsible for producing cerebrospinal fluid, which acts as a cushion and shock absorber for the brain and spinal cord. Case discussion: A 21-year-old female with no known medical conditions presented with a history of weakness and numbness in both lower limb for the past 1 years. Clinical examination and routine workup done with radiological investigation. An MRI of the spine showed a well-defined cystic lesion in the spinal canal measuring 22cm x 10.7cm x 8.2 cm, extending from the middle of the T11 to L3 vertebrae segment. After careful consideration, it was decided that surgery is necessary to relieve her symptoms and prevent further damage to her spinal cord. Discussion: Spinal arachnoid cysts, although rare, are a fascinating and often misunderstood condition. Usually seen in patients between the ages of 30-50 years with a slight female predominance, their exact cause is still unknown. Diagnosis of spinal arachnoid cysts can be challenging, as the symptoms may mimic those of other spinal conditions. Treatment options for spinal arachnoid cysts depend on the severity of symptoms and the size and location of the cyst. Conclusion: Spinal arachnoid cysts are rare but potentially debilitating conditions that can occur at any age and in any region of the spine. While their exact cause is unknown, advances in imaging technology have made it easier to diagnose and manage these cysts. Keywords: Spinal arachnoid cyst, extradural arachnoid cyst, arachnoid cyst.