A sacrococcygeal teratoma (SCT) is a tumor located at the base of the spine, often called the ‘tail bone’ in the area just above the buttocks. This kind of tumor is made up of different cells found during very early development. The tumor usually has both solid and cystic (fluid-filled) parts. Tumors with a greater cystic (fluid-filled) component may grow more slowly than those with more solid tissue. Some of the more solid tumors have a very large blood supply that can cause complications during the pregnancy and in the post-operative period. Large tumors can extend into the pelvis and affect other organs.
Sacrococcygeal teratoma is very rare and happens between 1 in 35,000 to 1 in 40,000 live births. The cause is unknown. Tumors that are found in the newborn period are usually benign (non-threatening) but a few may be cancerous.
SCT tumors are classified based on the position of the tumor.
- Type I: Completely outside the body.
- Type II: Mostly outside the body with a small part inside the pelvis
- Type III: Some part is outside the body with a large portion inside
- Type IV: Completely internal
Diagnosis of sacrococcygeal teratoma
Ultrasounds are used to measure the size of the tumor, assess for solid and cystic components, and growth rate. Using Doppler ultrasound we can detect the amount of blood flow to the tumor. Since the baby’s heart function can become strained if there is a large amount of blood flow to the tumor, a fetal echocardiogram is recommended to assess the baby’s heart function. Often, a fetal MRI is used to better determine the size and anatomy of the tumor.
Management of pregnancy
Testing to monitor for fetal distress during the pregnancy is very important. Some large tumors have a very high blood flow that causes a shift in blood flow away from the baby and towards the tumor. As it grows, it can cause the baby to become sick and hydropic. This means the heart begins to fail and the baby becomes swollen. Other possible complications include bleeding inside the tumor, development of excess amniotic fluid, and preterm labor.
Progressive hydrops can be associated with a swollen and sick placenta. There is a rare condition called ‘mirror syndrome’ where the mother ‘mirrors’ the baby’s sickness. If this occurs, the baby would be delivered.
Delivery of a baby with sacrococcygeal teratoma
It is advised that delivery of a baby with a sacrococcygeal teratoma be planned at a hospital that is prepared for high-risk births including a neonatal intensive care unit and pediatric surgical services. This will simplify communication between obstetrical, neonatal and pediatric surgical teams as well as limit the separation between mother and baby.
A Cesarean section is recommended for babies with larger tumors to prevent dystocia and reduce the risk of tumor rupture, or bleeding. Each pregnancy is evaluated on an individual basis.
University of Michigan is one of only a few centers nationwide at which the birth center is co-located within a comprehensive children’s hospital. This unique setting allows for seamless integration between our private-room birth center, state-of-the-art newborn intensive care unit (NICU), and access to around-the-clock pediatric surgical services in one convenient location.
Fetal treatment of sacrococcygeal teratoma
Open fetal surgery has been used in select babies with a sacrococcygeal teratoma with high blood flow and heart failure before 30 weeks gestation. The baby remains on placental support while the bulk of the tumor is removed. The baby is placed back in the uterus to recover with the hope of extending the length of the pregnancy.Premature delivery is common.
Minimally invasive fetal surgical techniques are being investigated as open surgery has significant risk to both mother and baby.
Postnatal treatment of sacrococcygeal teratoma
Babies with sacrococcygeal teratoma are evaluated immediately after birth.The neonatal doctors will check the baby’s breathing and heart rate, as well as place IVs for medicine and fluids. Larger tumors with a high blood flow cause considerable strain on the baby’s heart. The baby’s blood pressure and heart will be closely monitored and medicines can be used to help support the baby.
Once the baby is stabilized, the tumor can be removed. The coccyx (tail bone) is removed with the tumor to prevent reoccurrence. If left in place, the risk of the tumor returning is about 40%. All tumors are sent to pathology lab for analysis to determine if they are cancerous or benign. The vast majority of sacrococcygeal teratoma’s diagnosed in the newborn period are benign.
Large tumors may have bleeding complications. Sacrococcygeal teratoma’s located predominately in the pelvis may affect the muscles and nerves in the pelvis, altering bowel and bladder function. Recovery depends on the size of the tumor and the type of cells found in it. Equally important is the gestational age at birth and the degree of any associated malformations.
If babies do not have problems before birth or at delivery, the long-term outcome is usually very good. It is important to remember that even benign tumors may reoccur. All babies will require close monitoring during the first 3 years of life.
Future pregnancy risk
There have been a few reported cases of additional pregnancy with sacrococcygeal teratoma. Your doctor and a genetic counselor will review the risk in your family.