Sacrococcygeal teratoma: a case of mistaken identity.

We report a case in which prenatal diagnosis of fetal myelomeningocele led to termination of the pregnancy at 17 weeks. The diagnosis was made on the basis of prenatal ultrasound scan and raised maternal alpha-fetoprotein. Although the large cystic lesion arising in the sacral region appeared to confirm the diagnosis, autopsy examination revealed that this was a cystic sacrococcygeal teratoma. This case illustrates the importance of submitting all fetuses for full autopsy.