Sacrococcygeal teratoma (SCT) is a tumor that develops before birth and grows from a baby's coccyx — more commonly known as the tailbone. It is the most common tumor found in newborns, occurring in 1 out of every 35,000 to 40,000 live births.
Sacrococcygeal tumor. © CHOP/CFDT
The tumor is usually covered with skin, but may be covered by a thin, transparent tissue called a membrane. Most tumors have many blood vessels coming through them. They come in many different sizes, and sometimes they may grow outward from the back or toward your child's stomach.
SCT tumors are categorized according to their location and severity:
- Type I tumors are external (outside the body) tumors and are attached to the tailbone.
- Type II tumors have both internal (inside the body) and external parts.
- Type III tumors can be seen from the outside, but most of the tumor is inside your child's abdomen.
- Type IV tumors, the most serious tumors, can't been seen from the outside. They are inside the body at the tailbone level.
For an overview of the diagnosis and treatment of sacrococcygeal teratoma, watch our educational video below.
The signs and symptoms of sacrococcygeal teratoma depend largely on the size and location of the tumor. Some tumors can be diagnosed by ultrasound before your child is born. An abnormally sized uterus is typically the first sign that your baby may have a tumor. The size discrepancy can be due to a massive tumor or to polyhydramnios (excess amniotic fluid). Less common presentations include maternal preeclampsia. Fetal SCT may be cystic, solid or mixed in its sonographic appearance. The heterogeneous appearance of the mass may be due to mixed areas of tumor necrosis, cystic degeneration, hemorrhage or calcification.
Fetal sacrococcygeal teratoma ultrasound. ©CHOP/CFDT
If you are referred to the Center for Fetal Diagnosis and Treatment at Children’s Hospital of Philadelphia (CHOP), you will undergo a thorough day-long evaluation to confirm the diagnosis of sacrococcygeal teratoma. At the end of the day, our team will sit down with your family to explain your baby’s diagnosis, discuss treatment options, and answer your questions.
If your baby is prenatally diagnosed with fetal SCT, we will continue to monitor your pregnancy to watch for any growth of the tumor or changes in your baby’s condition that may require intervention. Your baby may need fetal surgery to remove the SCT if the size and severity of the tumor cause complications such as fetal hydrops that put you or your baby at risk.
Other tumors may not be visible until after your baby is born. After delivery, your child may have symptoms that indicate a possible SCT, such as being unable to urinate or have a bowel movement because the tumor is pressing on their bladder or rectum. Some children have no symptoms at all.
Risks and complications
When a prenatally diagnosed SCT is associated with fetal hydrops, the tumor can become life-threatening to both mother and baby.
Fetal sacrococcygeal teratoma MRI. ©CHOP/CFDT
In severe cases, the tumor "steals" blood from fetal circulation, causing the heart to work extra hard and making cardiac failure possible. Cardiac failure exhibits as fetal hydrops, a massive accumulation of fluid in the body of the fetus. In our experience, fetal hydrops associated with SCT is rapidly progressive and nearly always fatal.
For the mother, there is the risk of “maternal mirror syndrome” in which the mom’s condition parallels that of the sick fetus. When fetal hydrops is present, the mother may "mirror" the sick fetus, becoming ill with signs of preeclampsia. Preeclampsia, also called toxemia, is a condition characterized by pregnancy-induced high blood pressure, protein in the urine, and swelling due to fluid retention.
If your baby’s condition is stable with no high output cardiac failure (fetal hydrops), your pregnancy will be followed with regular ultrasound monitoring. If the SCT is small, a vaginal delivery at term may be planned.
If the SCT is large or if there is an excess of amniotic fluid (polyhydramnios), an early cesarean section is planned to avoid tumor rupture as well as the risks of preterm labor and premature delivery.
If fetal hydrops develops, you may be a candidate for fetal surgery.
Treatment for SCT involves surgery to remove the tumor. Depending on the diagnosis and severity of your child’s SCT, they may undergo fetal surgery to remove the SCT before birth, or they may have tumor resection surgery after they're born.
Fetal surgery is only indicated when fetal hydrops is present, putting your child’s life at risk.
Most fetal sacrococcygeal teratomas are not likely to be malignant, and the prognosis tends to be good after resection.
Updated: March 2014