Traumatic interdural arachnoid cyst in the upper cervical spine. Case report.

The case of an interdural arachnoid cyst of traumatic origin at the C3-5 level in an 18-year-old man was admitted to our hospital with a 1-year history of progressive weakness in left limbs and numbness below the clavicles is reported. He had had a C-2 fracture at the age of 9 years without definite neurological deficits. Magnetic resonance imaging revealed a cystic lesion in the C3-5 level. Laminectomy was performed, and an interdural cyst was found. Histological examination revealed fibrous thickening of the arachnoid membrane. A cyst located in the interdural space of upper cervical spine is extremely rare.