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
of the tumor, the pregnancy
will seem like a normal pregnancy.
Most GTD is benign
(not cancer) and does not spread, but some types become malignant
(cancer) and spread to nearby tissues or distant parts of the body.
Gestational trophoblastic disease (GTD) is a general term that includes different types of disease:
Placental-site trophoblastic tumors (PSTT; very rare).
Epithelioid trophoblastic tumors (ETT; even more rare).
Hydatidiform mole (HM) is the most common type of GTD.
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:
Gestational trophoblastic neoplasia (GTN) is a type of gestational trophoblastic disease (GTD) that is almost always malignant.
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:
Tubal pregnancy (the fertilized egg implants in the fallopian tube
rather than the uterus).
Placental-site trophoblastic tumors
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 signs or symptoms may appear months or years after a normal pregnancy.
Epithelioid trophoblastic tumors
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.
Age and a previous molar pregnancy affect the risk of GTD.
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:
when you are younger than 20 or older than 35 years of age.
Tests that examine the uterus are used to detect
(find) and diagnose gestational trophoblastic disease.
The following tests and procedures may be used:
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. A speculum
is inserted into the vagina and the doctor or nurse
looks at the vagina and cervix for signs of disease. A Pap test
of the cervix is usually done. The doctor or nurse also inserts one or two lubricated, gloved fingers of one hand into the vagina and places the other hand over the lower abdomen
to feel the size, shape, and position of the uterus and ovaries. The doctor or nurse also inserts a lubricated, gloved finger into the rectum to feel for lumps or abnormal areas.
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.
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. 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.