Obstetrics and Gynecology/Gestational Trophoblastic Disease

Gestational Trophoblastic Disease comprises a spectrum of tumors of the gestational trophoblast which range from completely benign to aggressively malignant.

There are four types of trophoblastic tumor


 * Hydatidiform Mole
 * Chorioadenoma Destruens (Invasive Mole)
 * Choriocarcinoma
 * Placental Site Trophoblastic Tumor

They all secrete the hormone human chorionic gonadotrophin (hCG).

Hydatidiform Mole
Hydatidiform Mole is a benign tumor of the trophoblast caused by abnormal fertilization.

Epidemiology
The incidence of hydatidiform mole differs depending on age, ethnic origin and classification of mole. The complete mole is most common in women under 20 and over 39, whilst the partial mole is more common in women between 20-30. The complete mole is most common among women from the Gulf region of the Middle East, while the partial mole is most common among South-East Asians. The incidence in the UK, Ireland and the USA is 1 in 2,000 pregnancies for the complete mole and 1 in 5,000 pregnancies for the partial mole.

Etiology and Pathogenesis
In the case of the complete mole, the ovum has lost all maternal genetic material. This is subsequently fertilized by a single sperm which duplicates, or undergoes dispermic fertilization. In the case of the partial mole, a normal ovum undergoes dispermic fertilization resulting in a complicated triploid structure containing vesicular cysts and fetal and placental tissue. The complete mole has 46XX chromosomes and the partial mole has 69XXY chromosomes. Both are at low risk of development into malignant tumors of trophoblastic origin.

Clinical Features
History
 * Vaginal Bleeding
 * Hyperemesis Gravidarum

Examination
 * Soft uterus enlarged inconsistent with dates
 * Pre-eclampsia
 * Thyrotoxicosis
 * Fetal heart sounds absent
 * Ovarian enlargement

Investigations
 * Raised hCG
 * Snowstorm appearance on Ultrasound Scan

Management
The treatment is surgical:
 * Group and hold
 * Evacutation suction
 * IV syntocinon

Chorioadenoma Destruens
Chorioadenoma Destruens is a malignant tumor of the trophoblast caused by abnormal fertilization. This results when a hydatidiform mole invades locally. 5-10% of all molar pregnancies are choriadenomas. A common complication is uterine rupture by the tumor itself, but metastasis is rare. Treatment is with chemotherapy and follow-up.

Choriocarcinoma
Choriocarcinoma is the most malignant of the trophoblastic tumors. The incidence of choriocarcinoma has been estimated at between 1 in 30,000 pregnancies to 1 in 60,000 pregnancies. They are highly invasive and metastasise early to the lungs and brain, among other locations. Half result from hydatidiform moles but they can, occasionally, result from normal pregnancies. Treatment is by chemotherapy and follow-up.