Final answer:
A benign molar pregnancy, also known as a hydatidiform mole, involves abnormal growth of the trophoblast tissue with no viable embryo and results in elevated human beta chorionic gonadotropin (B-HCG) levels.
Step-by-step explanation:
The type of gestational trophoblastic disease characterized as a benign molar pregnancy is known as a hydatidiform mole, often simply referred to as a 'molar pregnancy'. During normal embryonic development, the blastocyst implants into the endometrium. This involves the trophoblast, consisting of a fluid-filled shell of squamous cells that are destined to become the placenta and associated fetal membranes. The blastocyst's attachment to the uterine wall is critical for a successful pregnancy.
In the case of a molar pregnancy, there is an abnormal growth of the trophoblast tissue, leading to a pregnancy with no viable embryo. Such pregnancies produce elevated levels of human beta chorionic gonadotropin (B-HCG), which is a hormone that supports the pregnancy. The abnormal trophoblast tissue in molar pregnancies contains many cysts resembling a bunch of grapes, hence the term 'molar' from the Latin word for a mass or lump.