The sacrococcygeal region may be the origin of germinal tumors, of paragangliomas, and, rarely, of extradural myxopapillary ependymomas (MPE) in the newborn and child. A case is presented of a preterm child with an abdominal tumor, originating from the precoccygeal area, that turned out to be a teratoma with a component of an MPE. The high levels of alpha-fetoprotein in this preterm baby were initially misleadingly interpreted as a tumoral marker. The differential diagnosis and the difficulties in interpreting tumoral markers in infants are discussed.