Ultrasonographic features of the fetal Turner syndrome.

Recently we have examined six phenotypically female fetuses in whom the prenatal diagnosis of Turner syndrome was made. All had ultrasonographic examinations during the second trimester. Four showed a striking posterior cranio-cervical lymphocele (cystic hygroma) having a symmetric, trefoil , septated appearance in the coronal plane, combined with serosal fluid collections and cutaneous edema. Two fetuses were normal. It appears that Turner syndrome may present prenatally with variable findings. Perhaps such findings as cranio-cervical lymphocele (cystic hygroma) can undergo spontaneous remission, resulting in a liveborn baby with webbing of the neck. We have noted separation of the cervical vertebrae adjacent to the mass, which may interfere with growth and result in a short cervical spine. Amniocentesis should be done when a cystic mass centered on the posterior aspect of the head and neck is identified on ultrasonography. The constellation of findings, namely a trilobed septation of a cystic mass in the coronal plane, fluid collections in serosal cavities, and anasarca may be pathognomonic of Turner syndrome.