The first case, detected at 20 weeks' gestation, had a lumbar meningocele. At 30 weeks' gestation, direct US visualization revealed the division of the spinal cord into two hemicords. This patient illustrates an isolated type II diastematomyelia with a favorable prognosis. The second case, detected at 22 weeks' gestation, presented with disorganization of bony process of the vertebral column with a midline echogenic bony spur, asymmetrical hemicords, and a foot malposition. Fetal MRI at 26 weeks' gestation and CT/3D reconstructed at 32 weeks' gestation confirmed a type I diastematomyelia with orthopedic malposition. The third case, detected at 22 weeks' gestation, presented with widening of the lumbar canal and scoliosis. Prenatal work-up (US, MRI) disclosed other visceral malformations (pelvic kidney), which led to the assumption of a complex polymalformative syndrome. The pregnancy was terminated. Fetopathologic examination disclosed even more visceral malformations (anal atresia and unicorn uterus).

Infantile cortical hyperostosis (Caffey disease) is benign and self-limiting when it presents near or after birth but it is usually lethal when it presents earlier. We present the clinical, ultrasonic, radiographic, and pathologic findings in an instructive case of early onset prenatal cortical hyperostosis. The pregnancy of a 21-year-old woman was medically terminated at 30 weeks of gestation after a diagnosis of severe osteogenesis imperfecta. Prenatal ultrasounds showed short long bones. Postmortem radiographs showed hyperostosis in long bones, ribs and mandible. The affected skeleton showed marked bony sclerosis and ballooning of the diaphyses of the long bones with periosteal sclerosis. A complete autopsy showed characteristic histologic findings of infantile cortical hyperostosis in affected bones. A missense mutation (3040C --> T) in exon 41 the gene encoding the alpha 1 chain of type I collagen was found in fetus pulmonary tissue. Neither the severe form nor the mild form of prenatal cortical hyperostosis were thought to be related to collagen I mutations. Our study indicates that a heterozygous 3040C --> T mutation can also be found in lethal prenatal cortical hyperostosis.