The cause of choriocarcinoma is uncertain. It can arise from a normal pregnancy, a miscarriage, a tubal pregnancy or from either type of mole. How It Spreads Hydatidiform moles generally stay confined to the uterus. When it begins to invade the wall of the uterus, it is called an invasive mole. An invasive mole can penetrate the full thickness of the uterine wall and rupture, resulting in severe internal or vaginal bleeding.
Invasive moles can also spread to other organs, most commonly to the vagina and the lung.
This may be confusing since women with proven invasive moles who have metastases may also have choriocarcinoma. Although an invasive mole is more locally aggressive than a non-invasive mole, it is no more likely to develop into choriocarcinoma. An invasive mole develops in 10 to 20 percent of all complete moles and 5 to 10 percent of all partial moles. Choriocarcinoma develops in three percent of complete moles but rarely in partial moles. At Slightly Lower Risk Eating a diet high in vitamin A and having one or more children without having a previous abortion is statistically correlated with a lower than average risk of developing a complete mole.