Prenatal diagnosis and fetopathological investigation of dorsolumbosacral agenesis.

Sacral and lumbosacral spine agenesis, as characteristic signs of a rare congenital malformation--caudal regression syndrome--has been well described. However, dorsolumbosacral agenesis involving the lower thoracic, lumbar, and sacral vertebrae has rarely been reported, and prenatal diagnosis of this severe form has not been published yet. A 37-year-old woman (gravida 2, para 0) who had diabetes mellitus asked for termination of her pregnancy, because second-trimester ultrasound screening showed dorsolumbosacral agenesis of the fetus. Fetopathological examination confirmed the prenatal diagnosis and showed that the lower seven thoracic and all lumbosacral segments were absent. The noticed small "bony" structure in the lumbar region supported the idea that caudal regression syndrome can be regarded as a "multisegmental" spinal dysgenesis that involves the caudal part of the spine. Reliable prenatal diagnosis of dorsolumbosacral agenesis is possible by second-trimester ultrasound. The prenatal sonologist should always try to look for and assess abnormalities during examinations. Emphasis should be placed especially on those types that have a higher risk of being present in the fetus because of the known risk factors in the particular pregnancy. Fetopathological examination emphasized the suggestion that segmental spinal dysgenesis and caudal regression syndrome may represent two faces of a single spectrum of segmental malformations of the spine and spinal cord.