Gestational trophoblastic neoplasia (GTN) is an uncommon tumor that develops from an abnormal pregnancy. As a pregnancy develops part of the tissue becomes the embryo and the future baby and part of the tissue develops into the future placenta. It is this placental tissue that creates the trophoblastic disease. This disease has a very innocent forms and also has highly malignant types. The malignant conditions of this disease are highly curable with chemotherapy. Trophoblastic disease almost always starts in the uterus because that is where the pregnancy starts. Very rarely this disease may form in other areas of the body. This group of diseases is unique because the pregnancy tissue usually makes pregnancy hormone. This allows early detection of the abnormality and it allows confirmation that the problem has resolved when the pregnancy hormone has returned to normal.
Several common types of gestational trophoblastic disease are recognized. Each of these can give rise to persistent disease or to aggressive metastatic malignancy.
Hydatidiform mole is also referred to as a molar pregnancy. Most often there is no baby that ever develops with the pregnancy. This is most often resolved by a D&C to empty the uterus.
Invasive mole is a molar pregnancy complicated by the abnormal tissue invading into the wall of the uterus. That increases the risk of persistent disease. This may be recognized by continued abnormal bleeding after a pregnancy was terminated. Pregnancy hormone will stay elevated. Chemotherapy or removal of the uterus will be required for successful therapy.
Choriocarcinoma is a malignant form of trophoblastic disease that is very aggressive. It grows quickly and may spread to a variety of places including the lungs, the liver, and the brain. Choriocarcinoma may develop after a completely normal pregnancy or may be part of a molar pregnancy. It is more likely to present in an advanced state if it follows a normal pregnancy. The length of the pregnancy allows time for the trophoblastic disease to progress and spread and it may be considerable time after the pregnancy has been delivered before it is recognized that there is a problem. Chemotherapy will be required. Patients may also benefit from surgery to control uterine bleeding.
Placental site trophoblastic tumor is a rare type of trophoblastic disease. This tumor is unlikely to spread but it may deeply invade all the way through the wall of the uterus and into the neighboring tissues. This type is unique because it does not respond well to chemotherapy. Surgical removal is required.