Spinal neurenteric cyst is a rare congenital lesion that may occur either alone or in the context of a complex malformative disorder. Our case is unusual because of its rare intramedullary location, the association with an important intrathoracic development, and the age of the child at presentation (1 month). An anterior approach through a right-sided lateral thoracotomy was performed for a total resection of the intrathoracic part and a subtotal resection for the intramedullar portion. During 2 years of follow-up, the child presented no neurological deficit and post-operative magnetic resonance imaging found a small residue fixed on the anterior spinal cord without progression.