What type of molar pregnancy contains fetal tissue?

A partial mole is characterized by the presence of both abnormal placental tissue and some degree of fetal tissue. In this condition, there is typically a mixture of normal and abnormal chorionic villi, and the embryonic tissue may show signs of development, although it is often malformed or non-viable. The fetal tissue in partial moles can arise from fertilization of an egg by two sperm or an egg that has not undergone proper reduction in genetic content, leading to a triploid karyotype in many cases.

In contrast, a complete mole occurs when the egg is fertilized by one or two sperm, resulting in only abnormal placental tissue without any fetal tissue. Molar pregnancies with triploidy and choriocarcinoma do not involve viable fetal tissue; triploidy typically leads to severe fetal anomalies or demise, while choriocarcinoma is a malignant, gestational trophoblastic disease arising from trophoblastic cells, devoid of any normal fetal tissues. Thus, the presence of fetal tissue distinctly identifies partial moles in the spectrum of molar pregnancies.