Spinal extradural inclusion dermoid cyst mimicking pseudomeningocele, appearing after 17 years of meningomyelocele repair

Dermoid cysts are congenital cystic tumors arising from embryonic rests and commonest site is in the thoracic region of the spinal canal. The authors reported a case of dermoid cyst in a 17-year-old boy appearing after lumbar meningomyelocele repair at 2 months of age. The boy presented with 6 months history of gradually progressive globular swelling at the site of previous scar and weakness of the left foot. Preoperatively small extradurally protruding placode was seen attached to the swelling. The swelling was completely excised. At 1 year follow-up patient had improvement in foot weakness with magnetic resonance imaging showing no residual or recurrent lesion.