A 25-year-old pregnant woman experiences vaginal bleeding, and a subsequent ultrasound shows a fetus along with abnormal chorionic villi. What is the most likely diagnosis?

The most likely diagnosis in this scenario is a complete hydatidiform mole. This condition is characterized by the abnormal proliferation of trophoblastic tissue and can be associated with vaginal bleeding and ultrasound findings that show a cluster of abnormal chorionic villi.

In a complete hydatidiform mole, there is typically an absence of fetal tissue or development, and the appearance on ultrasound often shows a “grape-like” pattern of the villi due to the swelling of the trophoblastic tissue. This can lead to the formation of cystic spaces and represents an overgrowth of the placenta.

While partial hydatidiform moles do involve abnormal villi, they typically occur with some fetal tissue present and are caused by fertilization of an ovum by two sperm cells or by one sperm cell that duplicates its genetic material. The presence of both normal and abnormal chorionic villi often distinguishes partial moles from complete moles. Hence, the ultrasound findings showing only abnormal chorionic villi strongly suggest a complete hydatidiform mole rather than a partial one.

The other diagnoses, such as choriocarcinoma and placenta accreta, present with different clinical features and ultrasound findings. Choriocarcinoma often arises from molar pregnancies but involves malignant transformation