PREGNANCY-RELATED CONDITIONS

GESTATIONAL TROPHOBLASTIC DISEASE

Gestational trophoblastic disease (GTD) describes a group of tumors that develop after conception (fertilization of the egg) from trophoblastic tissue. Trophoblastic tissue forms early during pregnancy almost directly from the initial fertilized egg. Approximately at day 5, embryonic stem cells have divided enough to form a hollow mass with an inner bulk (inner cell mass) and an outer layer of cells (trophoblast). While the inner cell mass will go an to form the actual embryo and later fetus during a normal pregnancy, trophoblastic cells develop into the placenta.

In GTD, trophoblast cells degenerate into abnormal cysts and tumors - either instead of or in addition to a normal placenta. This can happen during pregnancy, often (but not always) impeding the healthy progression of the pregnancy, or after pregnancy - in some cases years after a successful delivery, during which trophoblastic cells can remain behind attached to the uterine wall unbeknownst to yourself or your doctor.

There are different types of GTD tumors, most of which are benign. In some cases however GTP can turn into malignant (cancerous) masses, in which case they can be dangerous and even life-threatening, especially if remaining undiagnosed. Below list can help you understand different types of GTD.

The worldwide prevalence of GTD is low. It appears that around 0.1% to 0.2% of pregnancies (1 to 2 out of 1,000) develop into gestational trophoblastic disease. However, if you or someone close to you are affected by GTD, the information here can help you understand the disease and treatments you may have to undergo.

Types

Risk Factors

Risk Factors

History of GTD
History of ovarian cysts
Advanced maternal age (> 35)
History of uterine fibroids or other tumors
High levels of human chorionic gonadotropin (HCG)
Hypertension (and/or preeclampsia)
Hyperemesis gravidarum
Hyperthyroidism

Types

Hydatidiform mole (molar pregnancy)

Hydatidiform moles (HM) are the most common type of GTD. They are usually benign and stay within the uterus. However, they can sometimes turn malignant. There are two different types of HMs: partial HM (1-5% risk of turning malignant) and complete HM (15-20% risk of turning malignant). A complete HM occurs when a defect egg cell that doesn't contain any maternal DNA (anucleate ovum) is fertilized (usually by two sperm cells, thus growing into a haploid but abnormal cell mass). The resulting cells, including placental cells, are abnormal and no fetus can form. The placental cells typically continue to grow into fluid-filled cysts that need to be removed from the uterus. In a partial HM, the egg cell does contain a full set of maternal DNA. However, cortical granulation action of the egg cell is defective, thus allowing multiple sperm cells (usually two) to enter the egg cell. Such a triploid (on all chromosomes) pregnancy continues to grow into both normal and abnormal placental tissue, as well as some fetal fragments (which are not viable ad are usually miscarried early on in the pregnancy).

Gestational trophoblastic neoplasia

Several different types of tumors classify as gestational trophoblastic neoplasia (GTN), most of them malignant. These tumors can be derived from partial or complete HMs that have turned cancerous, or from other abnormally developed trophoblastic (placental) tissue.

Choriocarcinoma and chorioadenoma destruens (invasive moles) are examples of cancer that can develop from HMs. While invasive moles invade the uterine wall but usually do not grow much beyond that, choriocarcinomas can and do spread to different organs outside of the reproductive tract, and even remote structures such as the brain.

Placental-site trophoblastic tumors (PTT) or epithelioid trophoblastic tumors (ETT) are other types of often cancerous gestational trophoblastic neoplasia. They all develop from trophoblastic tissue but are histologically slightly different (meaning that their genetic and cellular makeup varies to some degree). However, these cancers are extremely rare. They are also usually slow-growing and less aggressive than other types of GTN, which is why signs and symptoms can appear years after an otherwise healthy pregnancy (particularly PTT)

Symptoms

Bleeding or discharge (non-menstrual)
Pain or pressure in the pelvis
Nausea and vomiting
Anemia
Fatigue and Dizziness
Overactive thyroid (hyperthyroidism)
High blood pressure and shortness of breath

Treatments

Chemotherapy
Radiation therapy
Lumpectomy (removal of the tumor)
Hysterectomy (removal of the whole uterus)

Treatments