Closed spinal midline developmental defect was observed in three children, two girls aged 7 and 10 years and one boy aged 9 years. There were no similar cases in the families. The first signs appeared at approximately 6 months, 9 years and at birth. In the first two cases, developmental defects of the toes were followed a few months or a few years later by chronic ulcerations of the plantar surface of the foot. On physical examination there was a greater toe, amputation of the toes, perforating plantar ulceration, prolonged cauda equin and neurological disorders. Radiology revealed defective closure of the dorsal and/or lumbar vertebrae and lysis of the third phalanxes and magnetic resonance imaging showed diastematomyelia. The third child was born with a pilous nevus and a prolonged cauda equin. A soft subcutaneous tumor developed 3 years later over the lumbar area, increasing in size becoming quite voluminous and painful. In this case, there was no amputation of the toes or perforating plantar ulceration or neurological disorders. Radiography showed hemisacralization of L5 and spina bifida of S1. Magnetic resonance imaging showed a normal spinal cord with a tumor independent of the neural canal. Biopsy exeresis led to the diagnosis of neurofibroma.Closed spinal midline development defect occurs more readily in girls than in boys. Multiple and complex abnormalities are observed: diastematomyelia, diplomyelia, dermal fistulae, neuroenteral cysts, dysembryoplasic tumors, abnormal position of the spinal cord, and usually vertebral malformations. There are three types of clinical signs involving skin, bone and neurological manifestations. Radiological explorations should be completed with myelography and a computed tomography as well as magnetic resonance imaging to determine the extent of the malformations and possible surgical indications.