An Hydatidiform mole (H.mole or HM) is a type of gestational trophoblastic disease which involves the abnormal growth of cells inside a woman's uterus and usually starts in the tissue that would normally become the placenta, An HM is made up of villi, placental parts that have become swollen with fluid. The swollen villi grow in clusters that look like bunches of grapes

An HM is a mostly benign condition, that does not metastasize or invade deeply into tissue though it occasionally can be cancerous (malignant).  HMs are usually slow-growing and benign, although there is a chance a mole can become cancerous

There are two types of HM:

Complete H. Mole (no fetus forms)

A complete HM begins when sperm fertilizes an abnormal egg that doesn’t contain the mother’s DNA or a nucleus. It most often develops when either 1 or 2 sperm cells fertilize an egg cell that contains no nucleus or DNA (an “empty” egg cell).  All the genetic material comes from the father's sperm cell. Therefore, there is no fetal tissue. Instead of forming a fetus, the tissue grows into a mound of cells that look like grape-like cysts. A complete HM is much more likely to become cancerous than a partial HM.

Incomplete/partial HM (a fetus may form)

A partial HM begins when 2 sperm fertilize a normal egg, so there are two sets of DNA from the father. The result has some of the features of a complete HM but part of the fetus may form, but it’s not a viable (able to live) and there is no chance for fetal survival.

Treatment of H.Mole

Both partial and complete moles are usually removed by surgery, dilatation and curettage (D&C). Only a small number of women with partial moles need further treatment after initial surgery, and partial moles rarely develop into malignant GTD.

As many as 1 in 5 women will have some persistent molar tissue or persistent gestational trophoblastic disease (GTD), usually after a partial mole. Most often this is an invasive mole, not cancer. But in rare cases it is a choriocarcinoma, a malignant (cancerous) form of GT. Persistent gestational trophoblastic disease, GTD not cured after initial surgery requires further treatment.