Sacrococcygeal teratoma (SCT)

What is sacrococcygeal teratoma?

Sacrococcygeal (sae-crow-cox-i-gee-ul) teratoma (terr-uh-tome-uh) is the most common tumor found in newborns. "Sacro" refers to sacrum and "coccy" refers to coccyx. The sacrum is a curved triangular bone at the bottom end of the backbones, just before the coccyx. The coccyx is the last bone of the vertebral column. It is also known as the "tailbone.”

Sacrococcygeal identifies the location. Teratoma refers to the type of tissues that makes up these growths. They are comprised of chaotically arranged tissues of all types (fat, bone, nerves, etc.) that are found in an area that they are not normally seen. 

How common is sacrococcygeal teratoma?

Sacrococcygeal teratoma is rare, occurring in 1 in 35,000 to 40,000 live births. It is four times more common in females than males. 

What causes SCT?

Experts do not know the cause of SCT. One theory is that the tissue is a twin that didn’t correctly form. Another theory is that it is a growth from an abnormally placed set of germ cells or stem cells.

Types of SCT

Sacrococcygeal teratomas have been classified by the amount of the tumor that is outside the body. There are four classification groups: 

  • Type I is completely external, evident at birth and more easily surgically removed. Type I does not typically spread.
  • Type II has external and internal components. The internal portion is confined to the pelvic region. This type will spread in about 6 percent of cases. 
  • Type III also has external and internal components, but the internal portion extends into the abdominal area. Types II and III are also evident at birth, but surgically removing it may be more difficult because it requires access from both the back and from the front of your baby. Type III will spread in about 20 of cases. 
  • Type IV is completely internal. For this reason, it may go undiagnosed for some time. Later, symptoms may develop that warrant an investigation, and that may lead to a diagnoses. Type IV will spread in about 8 percent of cases. 

Complications of SCT

When parents hear that their child has a tumor, the first thing most ask is whether the tumor is cancer. Malignancy is not a primary cause of death for infants with SCT. 

Other complications for SCT include: 

  • Bleeding within the tumor
  • Development of hydrops
  • Risk of preterm labor due to the size of the tumor
  • Polyhydramnios (high volume of amniotic fluid)
  • Additional birth defects: About 11 to 38 percent of fetuses with an SCT will have other anomalies or birth defects. These associated defects increase the mortality rate as well.
  • Hydrops: The babies with large solid tumors are more prone to developing hydrops. This is, however, a small percentage of babies with SCT (less than 20 percent). Hydrops is an abnormal accumulation of fluid in two or more areas of the body. Some of the more common areas can include:
    • Fluid in the abdomen (ascites)
    • Fluid around the lungs (pleural effusion)
    • Fluid around the heart (pericardial effusion)
    • Extra fluid under the skin (anasarca) or scalp
    If hydrops develops after 30 weeks gestation, the mortality rate is about 25 percent. If, however, the hydrops develops before 30 weeks gestation, the mortality rate is more than 90 percent. Babies who develop hydrops early may become candidates for fetal intervention. This means some form of treatment may be available for the baby before he or she is born.

How big are the tumors?

Sacrococcygeal teratomas can be quite large. Size can vary, but many are about the size of the unborn baby. 

What are SCTs made of?

Some SCTs are cyst-type tumors, meaning they are filled with fluid. Others are solid tumors that may have a significant amount of blood flow through them. The most common type of SCT is a combination of both solid and cystic. 

Prenatal diagnosis of sacrococcygeal teratoma

About 60 percent of SCTs are diagnosed via prenatal ultrasound. As ultrasounds are becoming a normal part of routine prenatal care, this percentage is increasing. Doctors most often diagnose sacrococcygeal teratomas during a routine ultrasound or an ultrasound done because the uterine size is larger than it should be based on gestational dates. 

Babies with SCTs must be followed closely throughout the remainder of the pregnancy. We recommend a series of ultrasounds to observe and assess your baby for: 

  • SCT growth
  • Amniotic fluid volume
  • General well-being
  • Early evidence of hydrops

Your doctor probably will want to perform a series of echocardiograms or ultrasounds of your baby’s heart to assess for early signs of heart failure due to the blood flow required by a large solid SCT. 

A fetal MRI also may help better assess the blood flow in the tumor. Your obstetrician likely will refer you to a maternal-fetal medicine specialist (a doctor who handles high-risk pregnancies). You also likely will see a pediatric cardiologist (heart specialist) who will perform the fetal echocardiograms.

How does sacrococcygeal teratoma affect my baby?

Babies with a SCT normally do very well. However, they are at risk for preterm labor. This is partly due to the size of the tumor. The risk of preterm labor for babies with SCT is similar to the risk for a woman who is pregnant with twins. These pregnancies also can be complicated with an increased volume of amniotic fluid, which also carries with it an increased risk for preterm labor. 

If your baby has SCT, he or she is at risk for developing hydrops and/or heart failure, which will change the prognosis and chance of survival, especially if hydrops develops before 30 weeks gestation. 

SCTs are sometimes associated with maternal complications such as preeclampsia or mirror syndrome, especially if hydrops develops. If your baby has SCT, you will be monitored closely for early detection of complications so treatment can be started right away if necessary. 

If your baby has a SCT, the delivery method will be determined by the size of the SCT. If it is small (less than 5-10 cm) your physician may consider vaginal delivery. However, there are other issues to consider when thinking about vaginal delivery. These can include but are not limited to: 

  • Your health and the health of your baby
  • Whether you have previously delivered vaginally and the size of that baby
  • The position of your baby
  • Whether the SCT is solid or filled with fluid

In many cases, the best method of delivery of babies with SCT is cesarean section. The surgical incision on the uterus to remove your baby may need to be the classical type (up and down) to help the doctor deliver your baby without injuring the SCT. This is because SCT injury can result in bleeding in the tumor. Hemorrhage into the tumor can seriously compromise your baby, even to the point of being life threatening. 

How do you treat sacrococcygeal teratoma?

If your baby has a SCT, treatment will depend upon the size, type and location of the SCT, among other things. However, there are some standards of care that will be followed most of the time. These include:

  • Careful delivery: Babies with SCT require careful handling to prevent injury to the SCT. This is because bleeding into the teratoma can be life threatening for your baby. Immediate, careful monitoring of the baby is important in case something happens with the SCT. 
  • Umbilical artery catheter (UAC): The umbilical cord normally has two arteries and one vein. When your baby is born, doctors will place a special catheter into one of the arteries. This is called an umbilical artery catheter or UAC. Through this line, health care workers can:
    • Monitor blood pressure continuously
    • Draw blood for lab work
    With access to the umbilical artery, we will not have to do a needle stick to get blood samples for lab work.
  • Umbilical venous catheter (UVC): Staff also may place a special catheter through the vein in the umbilical cord. This is called an umbilical venous catheter or UVC. Through this line, we can give medication and fluids, and also check labs.
  • Other IV lines: Staff also may start other IV lines peripherally in the hands, arms, feet, lower leg or scalp.
  • Medications: Many times, babies with SCT need special medicine to help their heart pump well enough to supply blood to the whole body, as well as to the SCT. Your baby also may need antibiotics, especially after surgery.
  • Blood transfusions: Some babies with SCT will need blood transfusions. If your baby has severe bleeding in the tumor when he or she is born, doctors may give the blood transfusion right away in the delivery room.
  • IV nutrition: If your baby is born early, he or she may experience some complications related to that. If he or she is not able to eat for some time, we will provide special IV nutrition to keep your baby well nourished. This IV solution has two components. One of the fluids is yellow and contains the vitamins, minerals, protein and sugar necessary for a complete diet. The other solution is milky white and contains the fats. 

Will my baby need surgery?

All babies with SCT will need surgery, but we don’t usually perform surgery immediately. Once your baby is born, we will give him or her some time to adjust to life outside the womb before performing surgical procedures. However, if there are certain complications, we will send your baby for surgery right away. 

Complications may include:

  • Bleeding within the SCT
  • An SCT not completely covered by skin
  • Some other complicating factor

Once your baby has been stabilized after delivery, doctors will do an abdominal ultrasound before remove the SCT to help assess the SCT and determine how much is internal versus external. Doctors also may perform a CT or MRI scan before surgery to better assess the tumor. 

If your baby is born early and has a large SCT that is compromising heart function, surgeons will tie off the blood supply to the SCT. This will usually result in more normal heart function. Doing this will help your baby get a more stable respiratory status before doctors attempt surgery.

What can I expect after surgery?

Breathing support

Your baby will need support with breathing during and after surgery. To help your baby breathe, doctors will pass an endotracheal tube (ETT) between the two vocal cords into the windpipe. This tube is attached to a ventilator that can give your baby oxygen and help him or her breathe. Because of the position of the ETT, your baby won’t be able to make any noise. 


Your baby will receive different medications after surgery, including:

  • Medicine to keep your baby still and unable to touch or damage the surgical site
  • Medicine to keep your baby comfortable after surgery
  • Continued IV nutrition so your baby’s body is being nourished; this helps him or her heal from surgery
  • Antibiotics to prevent infections

Will I be able to help care for my baby after surgery?

Yes. Please ask your baby's nurse about ways to interact with and care for your baby. 

If you had planned to breastfeed your baby, you can begin to pump your breast milk while you are still in the hospital. A lactation consultant can answer your questions. Your milk will be frozen and stored in the Neonatal Intensive Care Unit (NICU) until your baby is ready for it. The NICU has breast pumps and private rooms available to you when you are visiting. 

When can my baby go home?

Your baby will go home when he or she is healed from surgery, and he or she is breathing well and eating enough to grow. 

A full-term baby with an SCT will have an average hospital stay of 2 to 4 weeks. If your baby was born early, the stay likely will be longer. 

What is my baby's long-term prognosis?

The long-term prognosis for babies diagnosed prenatally with a SCT is excellent. An important indicator of prognosis is the age at diagnosis and its removal. The earlier the prenatal diagnosis, the poorer the prognosis, especially if the diagnosis is the result of an ultrasound for maternal issues (such as uterine size larger than expected for gestational age). 

Cystic tumors carry a better prognosis than solid tumors because they are less likely to bleed or cause heart failure complications such as hydrops. 

There are risks that can compromise babies with SCT before and after birth. The two major complications that endanger these babies are difficulties with the removal and bleeding in the tumor. With surgical removal, experts recommend that the coccyx be removed along with the SCT to prevent the tumor from coming back (which is the most likely complication of SCT). The risk of the tumor coming back when the coccyx is not removed is 35 to 40 percent. 

Other long-term risks may include difficulty with urinating or passing bowel movements.

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