Gynecologic Oncology Program

Gestational Trophoblastic Disease

What Is Gestational Trophoblastic Disease?

Gestational trophoblastic disease is a group of diseases in which abnormal cells grow inside a woman's uterus in the tissues that are formed following conception (the joining of sperm and egg). The disease can take several different forms, and not all of them are cancerous. Most of them can be cured or successfully treated.

The main types of gestational trophoblastic disease are as follows:

Hydatidiform mole (also called a molar pregnancy) is the most common form of gestational trophoblastic disease. The sperm and egg cells have joined but have not developed into a normal fetus. Instead, the tissue that is formed resembles grape-like cysts.

In some cases, the mole also contains some fetal tissue (a partial mole), and in other cases it contains no fetal tissue (a complete mole). A complete mole has a slight chance of developing into a malignant tumor. If the mole invades the muscle of the uterus, it is called an invasive mole(or chorioadenoma destruens) and may cause the uterus to bleed. An invasive mole may also metastasize to other sites in the body. If an invasive mole is not cured with the typical treatments, it is often called persistent gestational trophoblastic disease. About 5 to 20 percent of hydatidiform moles progress to become more invasive tumors.
Choriocarcinoma is a malignant form of gestational trophoblastic disease. It may start from a hydatidiform mole or from tissues that remain in the uterus following a miscarriage, abortion, or normal pregnancy and delivery. The tumor grows more quickly and is more invasive than a mole. Because it is more likely to penetrate blood vessels, it is also more likely to spread to other parts of the body.
Placental-site trophoblastic tumor is a tumor that starts at the site where the placenta was attached to the uterus.

These tumors are very rare. Unlike other forms of gestational trophoblastic disease, placental-site tumors are not responsive to chemotherapy drugs and must be treated with surgery. Fortunately, they do not spread outside the uterus.

This page was last updated on: March 3, 2008.