Choriocarcinoma is a placental tissue derived cancer. Other older names for this are hydatidiform mole and gestational trophoblastic disease.
What is this strange sounding disease? “Chorion-” is a Greek word meaning “fetal membrane” or in plain English “placenta”. This is the fleshy tissue,rich in blood vessels and located between the uterine wall and the fetus in a pregnant woman. “-carcinoma” simply is another name for cancer.
So we can think of the choriocarcinoma being a cancer that is derived from placental tissue. “Hydatidiform mole” is also derived from the Greek and means literally a “mass consisting of water filled blisters in the uterus”. We would have to go back a few centuries, long before high-tech medicine, when this name was coined by physicians who looked at women who had died from complications of this disease. They found a mass in the womb with decomposed fetal parts and grape like cystic elements, which reminded them of fluid filled cysts. The shorter term “mole” is often used synonymously for brevity reasons.
Nomenclature regarding gestational trophoblastic disease
molar pregnancy : abnormal pregnancy where embryo died or did not develop
invasive molar pregnancy : mole is starting to invade the uterine wall
choriocarcinoma : established cancer, which spreads first locally, then systemically
There is another area of medicine where the strange name “hydatid disease” appears. This is in the context of the tapeworm echinococcus, which originates from dogs and where in the larval stage fluid filled sacs are formed in the liver of the affected human host. This has nothing to do with this chapter here, but historically it was the same group of pathologists and physicians in Europe who gave these diseases names, just to confuse us today.
“Gestational trophoblastic disease” would be the heading for this chapter. Just a brief explanation again what the language means: “gestational” means “pregnancy related”. “Trophoblastic” relates to the precursor tissue of the placenta, which is responsible for getting the small embryonic tissue implanted into the uterine wall. These are the same cells that later can turn aggressive and cancerous as in the case of choriocarcinoma.
There is a spectrum of gestational trophoblastic disease. After the birth of a baby in about 1 in 1200 of all pregnancies in the U.S. a small piece of placenta that stayed behind in the uterine wall after birth turned into a “benign hydatiform mole“. It’s called benign, because it is not cancer yet at this stage. However, in the following weeks or within 2-4 months it can very quickly turn malignant, meaning that it turns into an invasive cancer, called first “locally invasive mole” and then “choriocarcinoma“. In other words there is a spectrum from the benign mole to the invasive cancer.
The reason I included this type of cancer is that it is extremely important that both the mother of the new baby and the doctor have a suspicious mind about the possibility of a mole or choriocarcinoma. This is particularly the case when there is vaginal bleeding outside of the menstrual cycle and other bleeding irregularities post pregnancy. A simple blood test, as I am describing below, can rule this possibility out or confirm the problem. As always with cancer, early diagnosis is key, and there is a very effective treatment. Too many women die needlessly because of delayed diagnosis of this condition and once it has progressed to choriocarcinoma it is one of the most vicious tumors, which is extremely difficult to treat.
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