Harlequin fetus: three-dimensional sonographic findings and new diagnostic approach.

Congenital ichthyosis, otherwise known as harlequin fetus, is a severe, generally lethal, anomaly. Prenatal diagnosis is usually possible in families at risk but requires invasive fetoscopy for skin biopsy. The application of three-dimensional ultrasound enables a greatly improved analysis of the facial morphology and thus provides an important contribution to prenatal diagnosis. Although such three-dimensional diagnostic procedures are performed in specialized centers, sonographers should be aware of the signs observed at routine two-dimensional ultrasound examination in order to ensure appropriate referral for diagnosis. We describe two consecutive pregnancies of the same parents in which two- and three-dimensional ultrasound were used in the prenatal diagnosis of harlequin fetus.