Molar pregnancy and choriocarcinoma
This topic covers molar pregnancy (hydatidiform mole), an abnormal product of conception, and choriocarcinoma, the malignant tumour of trophoblast.
Molar pregnancy
Molar pregnancy is an abnormal product of conception in which there is usually NO fetus. It is more common in older women. The patient has vaginal bleeding early in pregnancy. The uterus is often found to be larger than expected for the period of pregnancy.
- Macroscopically: the uterus is filled with cystically dilated chorionic villi that look like a bunch of grapes. The enlarged villi are undergoing hydropic degeneration.
- Microscopically: edematous villi that contain no fetal blood vessels, and degrees of overgrowth of trophoblastic tissue that range from mild to marked.
Complete and partial mole
- Invasive mole: villi of a complete mole penetrate the myometrium and may reach vessels; it can cause uterine rupture and haemorrhage, and villi may embolise to the lungs without behaving as a true malignancy.
- Follow-up of every mole is by serial hCG measurement: a titre that fails to fall points to persistent trophoblastic disease.