General Information About Gestational Trophoblastic Disease
Key Points for This Section
- Gestational trophoblastic disease (GTD) is a group of rare diseases in which abnormal trophoblast cells grow inside the uterus after conception.
- Hydatidiform mole (HM) is the most common type of GTD.
- Gestational trophoblastic neoplasia (GTN) is a type of gestational trophoblastic disease (GTD) that is almost always malignant.
- Age and a previous molar pregnancy affect the risk of GTD.
- Possible signs of GTD include abnormal vaginal bleeding and a uterus that is larger than normal.
- Tests that examine the uterus are used to detect (find) and diagnose gestational trophoblastic disease.
- Certain factors affect prognosis (chance of recovery) and treatment options.
Gestational trophoblastic disease (GTD) develops inside the uterus from tissue that forms after conception (the joining of sperm and egg). This tissue is made of trophoblast cells and normally surrounds the fertilized egg in the uterus. Trophoblast cells help connect the fertilized egg to the wall of the uterus and form part of the placenta (the organ that passes nutrients from the mother to the fetus).
Sometimes there is a problem with the fertilized egg and trophoblast cells. Instead of a healthy fetus developing, a tumor forms. Until there are signs or symptoms of the tumor, the pregnancy will seem like a normal pregnancy.
Gestational trophoblastic disease (GTD) is a general term that includes different types of disease:
- Hydatidiform Moles (HM)
- Complete HM.
- Partial HM.
- Gestational Trophoblastic Neoplasia (GTN)
- Invasive moles.
- Placental-site trophoblastic tumors (PSTT; very rare).
- Epithelioid trophoblastic tumors (ETT; even more rare).
HMs are slow-growing tumors that look like sacs of fluid. An HM is also called a molar pregnancy. The cause of hydatidiform moles is not known.
HMs may be complete or partial:
- A complete HM forms when sperm fertilizes an egg that does not contain the mother’s DNA. The egg has DNA from the father and the cells that were meant to become the placenta are abnormal.
- A partial HM forms when sperm fertilizes a normal egg and there are two sets of DNA from the father in the fertilized egg. Only part of the fetus forms and the cells that were meant to become the placenta are abnormal.
Most hydatidiform moles are benign, but they sometimes become cancer. Having one or more of the following risk factors increases the risk that a hydatidiform mole will become cancer:
- A pregnancy before 20 or after 35 years of age.
- A very high level of beta human chorionic gonadotropin (β-hCG), a hormone made by the body during pregnancy.
- A large tumor in the uterus.
- An ovarian cyst larger than 6 centimeters.
- High blood pressure during pregnancy.
- An overactive thyroid gland (extra thyroid hormone is made).
- Severe nausea and vomiting during pregnancy.
- Trophoblastic cells in the blood, which may block small blood vessels.
- Serious blood clotting problems caused by the HM.
Gestational trophoblastic neoplasia (GTN) includes the following:
Invasive moles are made up of trophoblast cells that grow into the muscle layer of the uterus. Invasive moles are more likely to grow and spread than a hydatidiform mole. Rarely, a complete or partial HM may become an invasive mole. Sometimes an invasive mole will disappear without treatment.
A choriocarcinoma is a malignant tumor that forms from trophoblast cells and spreads to the muscle layer of the uterus and nearby blood vessels. It may also spread to other parts of the body, such as the brain, lungs, liver, kidney, spleen, intestines, pelvis, or vagina. A choriocarcinoma is more likely to form in women who have had any of the following:
- Molar pregnancy, especially with a complete hydatidiform mole.
- Normal pregnancy.
- Tubal pregnancy (the fertilized egg implants in the fallopian tube rather than the uterus).
A placental-site trophoblastic tumor (PSTT) is a rare type of gestational trophoblastic neoplasia that forms where the placenta attaches to the uterus. The tumor forms from trophoblast cells and spreads into the muscle of the uterus and into blood vessels. It may also spread to the lungs, pelvis, or lymph nodes. A PSTT grows very slowly and symptoms may appear months or years after a normal pregnancy.
An epithelioid trophoblastic tumor (ETT) is a very rare type of gestational trophoblastic neoplasia that may be benign or malignant. When the tumor is malignant, it may spread to the lungs.
Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer; not having risk factors doesn't mean that you will not get cancer. Talk to your doctor if you think you may be at risk. Risk factors for GTD include the following:
- Being pregnant when you are younger than 20 or older than 35 years of age.
- Having a personal history of hydatidiform mole.
These and other symptoms may be caused by gestational trophoblastic disease. Other conditions may cause the same symptoms. Check with your doctor if you have any of the following problems:
- Vaginal bleeding not related to menstruation.
- A uterus that is larger than expected during pregnancy.
- Pain or pressure in the pelvis.
- Severe nausea and vomiting during pregnancy.
- High blood pressure with headache and swelling of feet and hands early in the pregnancy.
- Vaginal bleeding that continues for longer than normal after delivery.
- Fatigue, shortness of breath, dizziness, and a fast or irregular heartbeat caused by anemia.
GTD sometimes causes an overactive thyroid. Symptoms of an overactive thyroid include the following:
- Fast or irregular heartbeat.
- Frequent bowel movements.
- Trouble sleeping.
- Feeling anxious or irritable.
- Weight loss.
The following tests and procedures may be used:
- Physical exam and history : An exam of the body to check general signs of health, including checking for signs of disease, such as lumps or anything else that seems unusual. A history of the patient’s health habits and past illnesses and treatments will also be taken.
- Pelvic exam : An exam of the vagina, cervix, uterus, fallopian tubes, ovaries, and rectum. The doctor or nurse inserts one or two lubricated, gloved fingers of one hand into the vagina and the other hand is placed over the lower abdomen to feel the size, shape, and position of the uterus and ovaries. A speculum is also inserted into the vagina and the doctor or nurse looks at the vagina and cervix for signs of disease. A Pap test or Pap smear of the cervix is usually done. The doctor or nurse also inserts a lubricated, gloved finger into the rectum to feel for lumps or abnormal areas.
- Ultrasound exam of the pelvis: A procedure in which high-energy sound waves (ultrasound) are bounced off internal tissues or organs in the pelvis and make echoes. The echoes form a picture of body tissues called a sonogram. Sometimes a transvaginal ultrasound (TVUS) will be done. For TVUS, an ultrasound transducer (probe) is inserted into the vagina to make the sonogram.
- Lumbar puncture : A procedure used to collect cerebrospinal fluid (CSF) from the spinal column. This is done by placing a needle into the spinal column. The CSF is checked for signs of cancer. This procedure is also called an LP or spinal tap.
- Blood chemistry studies : A procedure in which a blood sample is checked to measure the amounts of certain substances released into the blood by organs and tissues in the body. An unusual (higher or lower than normal) amount of a substance can be a sign of disease in the organ or tissue that makes it. Blood is also tested to check the liver, kidney, and bone marrow.
- Serum tumor marker test : A procedure in which a sample of blood is checked to measure the amounts of certain substances made by organs, tissues, or tumor cells in the body. Certain substances are linked to specific types of cancer when found in increased levels in the body. These are called tumor markers. For GTD, the blood is checked for the level of beta human chorionic gonadotropin (β-hCG), a hormone that is made by the body during pregnancy. β-hCG in the blood of a woman who is not pregnant may be a sign of GTD.
- Urinalysis : A test to check the color of urine and its contents, such as sugar, protein, blood, bacteria, and the level of β-hCG.
- The type of GTD.
- Whether the tumor has spread to the uterus, lymph nodes, or distant parts of the body.
- The number of tumors and where they are in the body.
- The size of the largest tumor.
- The level of β-hCG in the blood.
- How soon the tumor was diagnosed after the pregnancy began.
- Whether GTD occurred after a molar pregnancy, miscarriage, or normal pregnancy.
- Previous treatment for gestational trophoblastic neoplasia.
Treatment options also depend on whether the woman wishes to become pregnant in the future.