Sacrococcygeal teratoma (SCT) is a tumor that arises from the tip of the coccyx (tail bone). Although benign, it can become so enormous during pregnancy that the fetus can die from intrauterine cardiovascular failure. In such cases the only possible treatment is to remove it while the fetus is still inside the womb.
These tumors are visible in ultrasound scans from about the sixteenth week of pregnancy. If intrauterine surgery is being considered, an MRI scan is performed for more detailed diagnosis.
Prenatal intervention is indicated as soon as the fetus shows any signs of incipient cardiovascular failure. The tumor, which is usually huge (the size of an infant’s head), is removed by open surgery. In successful cases this returns the fetus to cardiovascular normality and uneventful subsequent development.
As this is a very traumatic and difficult operation (with a high risk of bleeding) in an already severely ill fetus, only about one in four fetuses survive. If, however, the fetus recovers well from the operation and no other serious problems arise later in pregnancy or after birth, the child’s prognosis for normal development is favorable.