A sacrococcygeal teratoma (SCT) is a type of tumor arising from the tailbone of a developing fetus. This type of teratoma can either grow externally from the tailbone or internally into the pelvis. While many sacrococcygeal teratomas are small and can be managed after birth, some may need fetal treatment.
What is sacrococcygeal teratoma?
One of the most common types of congenital germ cell tumors, a sacrococcygeal teratoma (SCT) is a mass located at the base of the tailbone, or coccyx, of a baby. It occurs in an average of one in every 35,000 births and is seen in three times more females than males.
It can vary in size, shape and consistency. While most are small and benign, some fetuses can develop larger growths or may have malignant cells.
There are a wide variety of types and sizes of tumors associated with this condition, however they are predominantly benign (non-cancerous) and can be successfully removed after birth in many cases.
Causes of sacrococcygeal teratomas
Causes of sacrococcygeal teratomas are unknown, though there are many theories.
Sacrococcygeal teratoma complications
Depending on the size of the sacrococcygeal teratoma, complications can vary. If the mass is small, often times there are no complications and the pregnancy will continue without problems. In these cases, the tumor can be successfully removed after birth with no prolonged impact to the baby or mother.
If, however, the tumor grows rapidly during the pregnancy, it can create a variety of complications that impact both the mother and baby. Because these tumors can become very large, severe cases put the fetus and mother at risk of:
Sacrococcygeal teratomas can also be tied to other congenital abnormalities such as myelomeningocele, so it's important to conduct a thorough examination to rule out additional complications.
How is a sacrococcygeal teratoma diagnosed?
Many sacrococcygeal teratomas are discovered through blood work or a routine ultrasound. At around 16 weeks of pregnancy, blood is drawn from an expectant mother to examine her levels of alpha-fetoprotein (AFP).
A high amount of AFP may be one indicator of this condition. Alternatively, the mass can also be detected through an ultrasound, appearing as a fluid-filled cyst on the baby's tailbone.
How are sacrococcygeal teratomas treated?
After a diagnosis, both mother and baby will be monitored often to watch the progression of the mass. A fetal echocardiogram will also be used to monitor the teratoma during pregnancy to track the development of heart failure and any risk of hydrops (fluid buildup).
Our fetal care team will also work with families to provide informed treatment plans based on the type, size, and composition of a fetal sacrococcygeal teratoma (verified by a fetal MRI). They'll also take into account the complications the mass is causing to determine if fetal surgery is required.
The standard treatment process for small, benign fetal sacrococcygeal teratomas includes:
- Observation: In pregnancies with no/low risk of cardiac complication, the teratoma is monitored with ultrasounds.
- Post-birth resection: Once the baby is delivered, the tumor is removed within the first 2-3 days of life. Babies usually stay in the hospital for 5-7 days after surgery until they are feeding normally with no concerns about pain or healing.
However, for larger or malignant tumors that are posing a risk to cardiac, lung or bowel functions, prenatal surgery may be recommended by our fetal care team.
Treatment for these types of sacrococcygeal teratomas includes:
- Aspiration of dominant cysts: In certain cases of sacrococcygeal teratomas, a dominant large cyst may pose a risk for obstruction or rupture. In this case, aspiration of the cyst contents (removal of fluid with a needle) can be performed in utero to stabilize the baby. Follow-up for this procedure includes frequent ultrasounds to monitor the baby’s growth, as well as fluid levels in the cyst.
- EXIT procedure: This is a special delivery technique where the sacrococcygeal teratoma is exposed through a limited incision in the uterus. The portion of the teratoma located outside the baby's pelvis is removed while on placental support.
Then, the uterus is closed, and the remainder of the tumor will be removed after the baby is born. This staged surgical process is used to prevent tumor rupture and hemorrhaging should the mother go into spontaneous labor.