Definition

Sacrococcygeal teratoma is a rare tumor that develops in the tailbone (sacrococcygeal) area of a baby, typically found in newborns. The term "teratoma" is derived from the Greek word for "monster-like tumor," as these tumors consist of different types of tissues such as hair, muscle, bone, or tooth tissue.

Sacrococcygeal teratoma is classified as a congenital disease because it develops during fetal development or shortly after birth. It is one of the most common tumors found in newborns, with an incidence of about 1 case per 35,000 to 40,000 live births.

Most teratomas are covered by a thin membrane or skin, and many contain blood vessels of varying sizes. While most sacrococcygeal teratomas are benign, they often require surgical removal due to their potential to grow large. In rare cases, sacrococcygeal teratomas may be malignant at birth.

These tumors are often discovered during pregnancy through routine ultrasound or prenatal check-ups. Sacrococcygeal teratomas are categorized based on their location and severity:

• Type 1: The tumor is located outside the body and is attached to the tailbone.

• Type 2: The tumor is partially external, with some portions growing inside the body.

• Type 3: The tumor is visible from the outside, but most of it is located inside the abdomen.

• Type 4: The most severe form, where the tumor is entirely within the tailbone and cannot be seen externally.

Causes

The exact cause of sacrococcygeal teratoma is still unknown. This type of tumor develops in the tailbone area and may protrude, growing into the pelvic cavity. Regarding the tumor's development mechanism, it is believed to originate from germ cells—cells produced during the embryogenesis process, which occurs about 8 weeks after fertilization when the embryo is forming in the womb.

Germ cells are the precursor cells to sperm in males and eggs in females. During embryonic development, these cells move to the testes in men or ovaries in women. Sacrococcygeal teratomas arise from these germ cells when errors occur during their migration to the testes or ovaries in the womb. The tailbone area is the most common site for this tumor.

Risk Factor

Sacrococcygeal teratoma is more commonly seen in girls than in boys, with a female-to-male ratio of approximately 3:1 to 4:1. Most cases of sacrococcygeal teratoma are sporadic, meaning they occur at random and do not follow any specific pattern.

Although there is no clear genetic link, a family history of twinning is present in 10-15% of patients. Currently, there is no significant difference in the occurrence of sacrococcygeal teratomas based on geographic location or ethnicity.

Symptoms

The symptoms of sacrococcygeal teratoma can vary depending on the size and type of the tumor. Smaller tumors often do not cause noticeable symptoms and can be surgically removed after birth.

Since many teratomas are detected during pregnancy, mothers may notice that their uterus is larger than expected for the gestational age. A larger-than-normal uterus may be a sign of excessive amniotic fluid, an enlarged placenta, or the presence of a tumor.

After birth, the tumor may be visible in the tailbone area. Additional symptoms that can be observed in the newborn include:

• Urine leakage from the genital area.

• Difficulty passing stool.

• Mucus discharge from the anus.

Diagnosis

Approximately 25-50% of sacrococcygeal teratoma cases are diagnosed while the fetus is still in the womb. During routine prenatal check-ups, the doctor will inquire about:

• Current gestational age.

• The mother’s pregnancy history.

• Any complaints or concerns during pregnancy.

• The mother’s diet and daily activities.

• Any medications taken before or during pregnancy.

• A family history of illness.

As part of the check-up, the doctor will assess the size of the uterus to see if it is larger than expected for the gestational age.

Supporting tests may include routine ultrasound, which can help the doctor assess:

• The shape of the fetus and identify any abnormal tissue or mass.

• The amount of amniotic fluid around the fetus.

• The estimated weight of the fetus.

• Whether fetal growth is progressing as expected for the pregnancy.

Additional tests may include:

• Blood clotting profile and platelet levels.

• Blood tests to measure AFP (alpha-fetoprotein) and β-hCG (human β-chorionic gonadotropin) levels.

After birth, a pediatrician will perform a thorough examination of the baby, checking for physical abnormalities, including the presence of a sacrococcygeal teratoma.

Management

The standard treatment for sacrococcygeal teratoma is surgery. Surgical procedures are typically performed after the baby is born, depending on the baby’s health and the type of sacrococcygeal teratoma present. Delaying surgery for too long may lead to complications. However, in some cases, surgery can be postponed until the child is over 2 years old, depending on the child's health condition.

If the sacrococcygeal teratoma is detected during pregnancy, the doctor will closely monitor both the mother and fetus. The size of the tumor and the condition of the baby’s heart will be closely observed. If the tumor exceeds 10 cm in size and makes a normal delivery difficult, a cesarean section will be necessary.

After birth, the baby's health will be monitored, and blood tests will be conducted to help the doctor determine the best course of action for treatment. 

Complications

Common complications of sacrococcygeal teratoma include hydrops fetalis, which is a dangerous buildup of fluid around the baby’s body. Additionally, the tumor’s blood vessels may rupture, causing bleeding around the tumor.

As adults, individuals who have recovered from sacrococcygeal teratoma may experience an increased risk of bowel dysfunction, urinary incontinence (difficulty holding urine), and chronic scarring.

Prevention

The exact cause of sacrococcygeal teratoma cannot be prevented, but the condition is often detected through routine pregnancy check-ups. It is essential for pregnant women to attend regular prenatal visits to monitor the development of the pregnancy and identify any potential issues early, allowing for timely intervention if necessary.

When to See a Doctor?

If sacrococcygeal teratoma is suspected, it must be addressed immediately by a doctor. If you notice a tumor growing in the tailbone area that does not improve, seek medical attention right away.

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