We report a case of vertebral malformation associated with diplomyelia believed to be a type II split cord malformation. Cervicothoracic level cases are exceptional. This article reports the case of an 11-year-old boy with no neurological symptoms who had not undergone surgery. The diagnosis was made during pregnancy by prenatal screening with ultrasound and MRI. Several embryological theories have been offered to provide an explanation for this syndrome. Close follow-up is mandatory. Surgery must only be considered if neurological deterioration occurs.