Fetal tumors may be diagnosed with ultrasound. The most common fetal tumor is sacrococcygeal teratoma (SCT). These tumors are 3 times more common in females. SCTs originate from the caudal (lowestmost portion) of the fetus. A common classification (Altman) places Type I tumors as being completely external to the fetus, type IV as being completely internal, and types II and III as being mostly external or mostly internal, respectively. SCTs can grow rapidly in utero and result in a number of complications, including intratumoral bleeding, destruction of red blood cells through the tumor, excessive amniotic fluid volume (polyhydramnios), overt fetal heart failure, or fetal death. Most SCTs can be managed conservatively, unless they show either pending or overt signs of fetal heart failure. Management of complicated SCTs depends largely on the gestational age. If the fetus is non-viable, in utero treatment of the fetal anemia or attempt at devascularization of the tumor have both been reported. Open fetal surgery to remove the tumor has also been proposed. If the fetus is viable, supportive treatment with fetal blood transfusions and premature delivery after steroid administration for fetal lung maturity enhancement has also been reported. Definitive treatment is undertaken after birth.

Other fetal tumors of importance include those that affect the fetal airway, including oral or neck masses. In most cases, expectant management is recommended and preparations are made to assure access to the fetal airway at the time of birth. In some cases, antenatal intervention has been proposed to avoid fetal death from fetal intratumoral hemorrhage. Kontopoulos and collaborators reported the successful removal of an oral teratoma in a fetus using endoscopic fetal surgery. In untreated cases, the fetal airway is secured at the time of delivery while the fetus is still attached to the placenta via the umbilical cord, with exposure of the fetal mouth through the uterine incision (so-called EXIT procedure, for Ex-utero Intubation). In-utero fetal intubation (INXIT?) has also been recently reported by some groups, including our collaborator Dr. Ramen Chmait in Los Angeles.

Other fetal tumors include intracranial, cardiac, mediastinal (within the middle of the chest) and abdominal. Fetal therapy is rarely if ever indicated in these cases and definitive assessment and management is reserved for the postnatal period. The option of pregnancy termination may be available up to certain gestational ages in different states. In continuing pregnancies, coordination with a team of specialists is arranged prior to delivery.