[A case of thoracic extradural spinal cord teratoma with neurological sequelae more than 10 years after surgery].

We describe a rare case of a 42-year-old man with extradural spinal cord teratoma who presented with left Brown-Séquard syndrome more than 10 years after surgery for a left posterior mediastinal tumor. When he was 29 years old, he underwent an operation for a posterior mediastinal tumor. Histological findings showed adenocarcinoma in teratoma. Ten years after the operation, the patient developed left leg weakness. Three years later, he developed superficial sensory disturbance in his right leg. MRI showed extradural tumor formation at the level of the Th 9 vertebra, which compressed the spinal cord from the left posterior side. At surgery, the tumor was well encapsulated and extended to the left posterior side of the spinal cord through the intervertebral foramen. The histological findings were almost identical to those from the mediastinal tumor. This dumbbell tumor apparently developed from the remainder of the posterior mediastinal tumor over a period of more than 10 years.