Gestational Trophoblastic Tum... Health Article

Definition

A gestational trophoblastic tumor (GTT) is a rare cancer that develops in tissues formed when a sperm fertilizes an egg but does not create a fetus.

Description

Also known as gestational trophoblastic neoplasms (GTN), these highly curable malignancies originate inside the uterus, in cells (trophoblasts) that make up one layer of the placenta. The most common types of GTT are hydatidiform mole (molar pregnancy) and choriocarcinoma. Placental-site trophoblastic tumor is an extremely rare type of GTT. It originates at the place where the placenta was attached to the wall of the uterus.

Hydatidiform mole

A hydatidiform mole forms when sperm and egg cells unite but do not create a fetus. Cells that form the placenta continue to grow until they look like drops of rain or clusters of grapes. Also known as molar pregnancy, a hydatidiform mole does not spread beyond the uterus.

Choriocarcinoma

Characterized by rapid growth and heavy bleeding, this aggressive, invasive tumor is considered a medical emergency and requires immediate medical attention. Although choriocarcinoma usually originates in a hydatidiform mole, it can also develop in tissue that remains in the uterus following a normal delivery, an abortion, or an ectopic pregnancy.

A malignancy of the trophoblastic cells that form the lining of the uterus (epithelium), choriocarcinoma can spread (metastasize) to any part of the body. Metastasis begins at an early stage of the disease and usually involves the lungs, vagina, pelvis, brain, and/or liver. Symptoms of lung metastasis include severe shortness of breath (respiratory insufficiency) and coughing up blood. Irregular, abnormal bleeding can indicate that choriocarcinoma has invaded the vagina. The central nervous system (CNS) is rarely affected unless the disease has spread to one or both lungs; a patient whose brain does become involved may experience headaches, seizures, and stroke-like symptoms. More rarely, choriocarcinoma may spread to the kidneys, spleen, and/or gastrointestinal tract.

Demographics

GTTs occur only in women of childbearing age. These tumors are most common:

• before the age of 16
• after the age of 40
• in women who have had them before
• among women who are poor

Accounting for only 1% of all gynecologic malignancies, GTTs are five times more common in Africa and Asia than in Europe and North America. In the United States, hydatidiform mole occurs in only one of every 1, 500 to 2, 000 pregnancies.

Causes and symptoms

The cause of GTTs is unknown. A woman's chance of developing a second GTT, while still very low, is about twice as great as her risk of developing a first one.

Symptoms of hydatidiform mole

The most common symptoms of hydatidiform mole are vaginal bleeding and severe morning sickness during the first trimester of pregnancy. Other symptoms that suggest a hydatidiform mole include:

• a uterus larger than expected at a particular stage of pregnancy
• a uterus enlarged on only one side
• a fetus not visible on a sonogram
• absence of fetal heart sounds
• passage of clots with the color and consistency of prune juice or of finger-like structures containing fetal blood cells (villi)
• toxemia
• ovarian cysts
• hyperthyroidism

Recurrent bleeding often causes iron deficiency anemia in women who have had a hydatidiform mole. Although molar pregnancy is almost always diagnosed during the first trimester, it is often difficult to distinguish this condition from the early stages of a normal pregnancy. A woman should see her doctor if she experiences abnormal bleeding or cannot feel her baby move when she should.

Symptoms of choriocarcinoma

This GTT occurs in 4% of women whose hydatidi-form mole was surgically removed or treated with radiation therapy. Following term pregnancies or abortion, the incidence of choriocarcinoma is 1 in 40, 000.

A doctor should always consider choriocarcinoma when vaginal bleeding persists after a woman has given birth. Other abnormalities commonly associated with choriocarcinoma are unusual and unexplained neurological symptoms in women of childbearing age and lesions that can be seen on a chest x ray but do not cause shortness of breath or other symptoms.