Prenatal diagnosis of sacrococcygeal teratoma: sonographic-pathologic correlation.

The prenatal sonograms of 15 fetuses with sacrococcygeal teratoma were reviewed to determine the sonographic appearance and the role of sonography in the obstetric management. Each tumor appeared as a large mass arising from the fetal rump. The teratomas exhibited three sonographic patterns: nine were mixtures of cystic and solid components in equal proportions, four were predominantly solid with a few scattered anechoic areas, and two were unilocular cystic masses. Calcifications were detected in six cases. There was no correlation between the sonographic appearance and the presence of immature or malignant components. Ultrasonography allowed visualization of an intraabdominal component in six cases and assessment of findings that were of prognostic importance. Prenatal detection and size determination of the external component can play an important role in planning obstetric management because fetuses with a large tumor should be delivered by cesarean section to avoid dystocia and catastrophic hemorrhage during delivery.