Posterior midline cervical fetal cystic hygroma.

Posterior midline cervical cystic hygromas (PMC) are frequently found associated with chromosomal aberrations and usually do not survive. The present report illustrates diagnosis of this condition by sonography in an 18 weeks old fetus and an amniocentesis revealed 45 x0 karyotype and increased concentration of alpha-fetoproteins. Pregnancy was terminated in view of Turner's syndrome. The etiology and natural history of the condition is reviewed.