Antenatal diagnosis of sacrococcygeal teratomas: prognostic features

During a 6-year span the prenatal ultrasound diagnosis of a sacrococcygeal mass was made eight times at the High-Risk Perinatal Centers of Case Western Reserve University. The gestational age at the time of diagnosis ranged from 21 to 35 weeks. In one of the pregnancies, the affected fetus was one of a set of fraternal twins. Two patients were delivered vaginally and five were delivered by cesarean section. One fetus died in utero. In seven the diagnosis of sacrococcygeal teratoma (SCT) was confirmed histologically. In the eighth the lesion was a fungating malignant melanoma of the lower sacral region. The decision as to mode of delivery was made based on the size of the tumor relative to the biparietal diameter and fetal presentation. Four of the six remaining patients with SCT survived. In the three with fatal outcome, the ratio of infant weight to tumor weight was below 1.7. This measurement is a clear indication of the very large size of these lesions. The increased blood flow through these tumors can lead to fetal cardiac failure, hydrops, and death. With the almost routine use of ultrasound, more SCT may be identified antenatally. Included in this group and referred to tertiary care centers will be nonviable fetuses as well as very small fetuses with exceptionally large tumors; this will raise the overall mortality in this group of patients traditionally regarded by pediatric surgeons as having a good outlook.