Types
GTD is the common name for five closely related tumours (one benign tumour, and four malignant tumours):
- The benign tumour
- Hydatidiform mole
Here, first a fertilised egg implants into the uterus, but some cells around the fetus (the chorionic villi) do not develop properly. The pregnancy is not viable, and the normal pregnancy process turns into a benign tumour. There are two subtypes of hydatidiform mole: complete hydatidiform mole, and partial hydatidiform mole.
- The four malignant tumours
- Invasive mole
- Choriocarcinoma
- Placental site trophoblastic tumour
- Epithelioid trophoblastic tumour
All five closely related tumours develop in the placenta. All five tumours arise from trophoblastic cells. The trophoblast is the membrane that forms the wall of the blastocyst in the early development of the fetus. In a normal pregnancy, trophoblastic cells aid the implantation of the fertilised egg into the uterine wall. But in GTD, they develop into tumour cells.
Read more about this topic: Gestational Trophoblastic Disease
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