Sacrococcygeal Teratoma
Overview
Sacrococcygeal Teratoma / SCT is a tumor made up of tissues from the three primary layers of cells defined in embryos, or germ layers. Sacrococcygeal Teratoma / SCT appear in the lower back and buttocks. The tumors can grow at an unpredictable rate to very large dimensions and present both inside and outside the fetal pelvis. Some tumors are diagnosed in utero, others at birth.
Though a rare condition (1 in 35,000-40,000 births), Sacrococcygeal Teratoma / SCT is one of the most common tumors in newborns. Females are four times more likely to be affected than males. Malignancies are more frequent in males.
Source: Fetal Care Center of Cincinnati
Symptoms
The following are the most common symptoms of a teratoma. However, each child may experience symptoms differently. Symptoms vary depending on the size and location of the tumor. Symptoms may include:
- a tumor, swelling, or mass that can be felt or seen
- elevated levels of alpha-fetoprotein (AFP)
- elevated levels of beta-human chorionic gonadotropin (B-HCG)
- constipation, incontinence, and leg weakness, if the tumor is in the sacrum (a segment of the vertebral column that forms the top part of the pelvis) compressing structures
Source: Children’s Hospital Boston
Causes
The cause is not known. One theory is it is a failed twinning attempt. Another is it is a growth from an abnormally placed set of germ or stem cells.
Source: Children’s Hospital of Wisconsin
Diagnosis
Fetal teratomas:
Sacrococcygeal Teratoma / SCT is detected by ultrasound as a mass on the fetal buttocks associated with a uterus larger than it should be at a specific gestational age. The reason for this is often polyhydramnios caused by hyper-filtration of the kidneys due to the high output state these tumors cause. An extremely large Sacrococcygeal Teratoma / SCT can displace the pelvic or abdominal structures of the fetus. Some fetal tumors have been reported as large as 25 cm by 20 cm. Abnormalities of the nervous, cardiac, gastrointestinal, urogenital or musculoskeletal systems may be associated with Sacrococcygeal Teratoma.
Newborn teratomas:
Teratomas in the newborn are often detected on prenatal ultrasound. Other diagnostic procedures can include:
- biopsy - a sample of tissue removed from the tumor and examined under a microscope.
- complete blood count (CBC) - a measurement of size, number, and maturity of different blood cells in a specific volume of blood.
- additional blood tests - may include blood chemistries, evaluation of liver and kidney functions, and genetic studies.
- multiple imaging studies, including:
- computerized tomography scan (also called a CT or CAT scan) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
- magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
- x-ray - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.
- ultrasound (also called sonography) - a diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels.
Source: Fetal Care Center of Cincinnati, Children’s Hospital Boston
Prognosis
- Most fetuses with sacrococcygeal teratoma do well with surgical treatment after birth. These tumors are generally not malignant. Babies with small tumors that can be removed along with the coccyx bone after birth can be expected to live normal lives, although they should be followed for development of tumors later in life, using a simple blood test for alpha feto-protein. Fetuses with larger tumors or tumors that go up inside the baby’s abdomen will require more complex surgery after birth, but in general do well. Again, they will have to be followed with blood tests for several years. Fetuses with very large tumors, which can reach the size of the fetus itself, pose a difficult problem both before and after birth.
- Although the majority of these tumors are histologically benign, they are associated with significant morbidity and mortality due to secondary effects of the sacrococcygeal teratoma: prematurity of the infant, dystocia and traumatic delivery, exsanguination from hemorrhage into the tumor, or high output failure secondary to a steal phenomenon. The prognosis for cure is generally good after a successful complete removal of benign sacrococcygeal teratoma.
Source: The Fetus.net, The Fetal Treatment Center
Treatment
• While the mortality rate for Sacrococcygeal Teratoma / SCT diagnosed in a newborn is less than five percent, the mortality rate for Sacrococcygeal Teratoma / SCT in utero is 50 percent. Thus, there should be close observation during pregnancy. Weekly ultrasounds should be performed to confirm or rule out associated abnormalities, monitor amniotic fluid, tumor growth, fetal well being and early signs of hydrops (in utero heart failure). Weekly fetal echocardiograms will detect early changes in cardiac function with increases in combined ventricular output, increased aortic flow and dilatation of the SVC. After 30 weeks of gestation, weekly amniocentesis may be recommended to determine pulmonary maturity, which may allow for an early delivery.The mother should be observed for signs of preterm labor, preeclampsia (toxemia), or the "mirror syndrome," in which the mother mirrors the symptoms of the fetus when placentomegaly has developed. Delivery should occur in a tertiary care hospital where neonatologists and pediatric surgeons are available to provide care.
• Most newborns that are born with SCT will undergo surgery to remove the mass and reconstruct the perineum after birth. These babies usually do very well. A small number of patients, however, experience progressive enlargement of the tumor very quickly prior to birth, which can lead to heart failure (hydrops). These are the patients who are offered prenatal intervention.
Source: Fetal Care Center of Cincinnati, Children’s Hospital Boston
Resources
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