Introduction: An intraspinal teratoma that is located entirely extradurally is unusual both in children and in adults.
Case history: The authors present a case of an 8-month-old male infant with an extradurally arising intraspinal mature teratoma located from T-2 to T-4, who had suffered from progressive paraparesis (grade 1). The patient did not have any stigmata or anomalies suggesting spinal dysraphism. Spinal MRI showed a cystic extradural mass markedly compressing the dural sac. On operation, the only way of getting sufficient space for exposure of the whole tumor was to perform hemilaminectomies with preservation of facetal areas to prevent postoperative instability. The tumor was well encapsulated and located entirely extradurally, and the cystic portion was occupied with yellowish fluid. The site of tumor occurrence was the spinal root sheath, mimicking a neural sheath tumor. Paraparesis had improved markedly to grade 4 by the time of the neurological examination 3 months after operation.