What Is a Teratoma? Symptoms, Causes and Treatment

A teratoma is a rare tumor that can contain different tissue types and is a germ cell tumor subtype. Germ cells are the body's reproductive cells: egg cells in women and sperm cells in men. Teratomas most commonly occur in the ovaries, testicles and tailbone. However, they can also develop near the midline, in the mediastinum (chest cavity), retroperitoneum (back of the abdomen), and brain and spinal cord.

Teratomas can occur in newborns, children or adults. They may be benign, meaning they may not be cancerous or malignant. The main treatment for teratomas is surgery.

What Is a Teratoma?

A teratoma is a type of tumor that can contain many different tissues. Its name comes from the Greek “monstrous (monster) tumor”.

For example, teratomas may contain the following tissues;

• Hair
• Bone
• Teeth
• Muscle
• Organs

Teratomas may commonly occur in the following areas;

• Gonads (ovaries and testicles)
• Extragonadal areas (lower spine, chest, abdomen, brain and spinal cord)

We generally classify teratomas into 2 subgroups:

• Mature or
• immature, meaning not mature.

Mature teratomas: These tumors are the most common type of extracranial germ cell tumor. Mature teratomas are benign tumors and have no possibility of becoming cancerous. They usually occur in the sacrum or tailbone of newborns, or in the testicles or ovaries at the onset of puberty. Under a microscope, mature teratoma cells look almost like normal cells. Some mature teratomas secrete enzymes or hormones that cause signs and symptoms of disease.

Immature teratomas: These tumors usually occur outside the gonads in young children or in the ovaries at the onset of puberty. Their cells look very different from normal cells under a microscope. Immature teratomas may be cancerous and spread to other parts of the body. They usually contain several different tissue types, such as hair, muscle and bone. Some immature teratomas secrete enzymes or hormones that cause signs and symptoms of disease.

How Common Are Teratomas?

Teratomas are rare tumors detected in children. The two most common teratomas are sacrococcygeal teratomas (extragonadal) and mature cystic teratomas of the ovary (gonadal). Sacrococcygeal teratomas, which develop at the base of the spine, are the most common tumors in newborns, occurring in 1 of every 20,000 to 40,000 births annually. Mature ovarian teratomas are the most common ovarian tumor in young women, particularly in the second or third 10 years of life. Other types of teratoma, including testicular and mediastinal teratomas, are much rarer.

In very rare cases, a type of teratoma called "fetus in fetu" may occur. This type of teratoma looks like an underdeveloped fetus within the body of a healthy person. One view holds that the fetus in these teratomas is the remnant of a twin that could not survive and was later enclosed by the surviving sibling, while another view assumes that the mass is a highly developed teratoma.

What Are the Symptoms of a Teratoma?

Teratoma symptoms can vary depending on the size and location of the tumor. In some cases, a teratoma may cause no symptoms and the mass is noticed only when it has grown considerably.

Possible teratoma symptoms may include;

• A mass, swelling or lump that the person can feel or see
• Constipation or urinary incontinence
• Weakness in the legs
• Pain in the abdomen
• Difficulty breathing

If a teratoma secretes hormones, it can cause noticeable symptoms in children before puberty and may cause puberty to start early. These hormonal changes can occur in both girls and boys.

What Are the Causes and Risk Factors for Teratomas?

The exact cause of teratomas is currently unknown. However, research suggests that teratomas occur because of changes in embryonic stem cells. These special cells are pluripotent, meaning they can turn into any other cell in the body.

These tumors are thought to arise from the three developmental germ layers that form the fetus: the ectoderm, mesoderm and endoderm. These germ layers are made of germ cells that can form various tissues, including fat, muscle, teeth, nails and hair. During fetal development, some of these germ cells do not differentiate, retaining the ability to turn into other cell types. These germ cells then migrate through the midline until they reach the primitive gonads, where they may remain for decades before eventually turning into eggs or sperm. A problem in the differentiation process of these cells is thought to lead to teratoma development, explaining why teratomas may occur in the gonads or along the germ cell migration route.

Factors that increase teratoma risk may also vary depending on the type of teratoma. For example, researchers suggest that risk factors for testicular teratomas may include;

• Low birth weight and short length at birth
• Cryptorchidism (failure of the testicles to reach their proper location in the womb)
• Hypospadias (the urinary opening being on the underside rather than the tip of the penis in children)
• Bleeding during pregnancy
• Older maternal age during pregnancy
• Jaundice
• Failure to deliver the placenta within 30 min after birth

Risk factors for ovarian teratomas becoming malignant may include;

• Older age
• Large tumor size
• Having reached menopause
• High levels of a protein called cancer antigen 125 (CA-125)

How Is a Teratoma Diagnosed?

In addition to a medical history and physical examination, we often request the following tests to help diagnose a teratoma;

• To show the location of a potential tumor, magnetic resonance imaging (MRG), computed tomography (BT) or ultrasound imaging techniques
• Alpha-fetoprotein (AFP) and human chronic gonadotropin (hCG) blood tests, with high levels indicating the presence of a teratoma
• Complete blood count
• Liver, kidney and lung function tests
• Biopsy of the tumor

However, a teratoma may also be diagnosed incidentally during tests performed to diagnose another disease or condition.

After diagnosis, we stage the tumor from 1 to 4. This classification indicates the size of the tumor and whether it has spread to other parts of the body. A stage 1 teratoma is small and localized, while a stage 4 teratoma is larger and may have spread to different areas.

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How Is a Teratoma Treated?

In most cases, teratoma treatment involves surgically removing the entire tumor. The person may also need chemotherapy after surgery.

The type of teratoma and whether it is malignant may affect treatment options.

For example, there are 4 standard treatments for people with ovarian teratomas;

• Surgery
• Close monitoring
• Chemotherapy
• Radiation therapy

For a woman with a stage 1 ovarian teratoma, surgery may be the only treatment needed if the tumor is small and easy to remove. If the person needs chemotherapy, usually the chemotherapy regimen called PEB is used. This chemotherapy regimen includes cisplatin, etoposide and bleomycin.

Summary

A teratoma is a type of germ cell tumor that can be benign or cancerous. These tumors may contain several different tissue types, such as hair, muscle and bone. They usually occur in the ovaries in women, the testicles in men and the tailbone in children. Sometimes, however, they may occur anywhere in the body.

Treatment options for teratomas vary depending on the location, size and stage of the tumor, but generally involve surgical removal of the tumor and chemotherapy.

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• Related topic: Testicular Cancer Symptoms, Stages and Treatment