Congenital spinal arachnoid cysts: report of 2 cases with review of the literature.

Two cases of congenital spinal arachnoid cysts with paraparesis are presented. Case 1, a 16-year-old male patient, had a 2-year history of progressive weakness of the lower limbs. Postmyelographic axial computed tomography (CT) and myelography revealed a dorsally located extradural mass. The configuration of the mass was further assessed with magnetic resonance imaging (MRI). He underwent laminectomy from T8 to L1 with total excision of an extradural arachnoid cyst. A communication with the subarachnoid space found at the T8 level was surgically closed. The patient made an uneventful recovery. Case 2, a 9-year-old girl, developed paraparesis and the cauda equina syndrome two days prior to admission. Postmyelographic CT and myelography revealed an anteriorly located intradural mass. She underwent laminectomy from C6 to T2 and partial removal of an intradural arachnoid cyst. One week later, her neurological functions had recovered completely. The literature dealing with this rare spinal lesion is also reviewed.