Ring chromosome 21 presenting with sacrococcygeal teratoma: prenatal diagnosis, molecular cytogenetic characterization and literature review.

We present perinatal findings and molecular cytogenetic characterization of a prenatally detected sacrococcygeal teratoma associated with mosaic r(21). This is the first report of mosaic r(21) presenting with a fetal sacrococcygeal teratoma. We discuss cytogenetic abnormalities associated with fetal sacrococcygeal teratomas.