Choriocarcinoma: A highly malignant tumor that arises from trophoblastic cells within the uterus. Choriocarcinoma tends to be invasive and to metastasize early and widely through both the venous and lymphatic systems. Choriocarcinoma is one of the two types of gestational trophoblastic tumor, the other being hydatidiform mole.
Choriocarcinoma may follow any type of pregnancy. It is especially likely to occur with a hydatidiform mole (molar pregnancy). About 2 to 3% of hydatidiform moles are complicated by the development of choriocarcinoma.
The prognosis for women with metastatic choriocarcinoma was once grim. It has markedly improved with the advent of multidrug chemotherapy. Patients with high-risk metastatic disease usually need aggressive multidrug chemotherapy. Women with low-risk metastatic disease are sometimes treated with a single drug. Overall, the cure rate for high-risk patients is 60 to 80%.