**Question:** Ultrasound of a 36-year-old gravida reveals small grape-like cystic structures without evidence of a developing embryo. A diagnosis of complete abortion is likely based on this finding. Which of the following terms best describes this situation?

A. Ectopic pregnancy
B. Molar pregnancy
C. Incomplete abortion
D. Chorioangioma

**Correct Answer:** B. Molar pregnancy

**Core Concept:** Abortion is the spontaneous expulsion of a fetus from the uterus before the fetus reaches viability (28 weeks gestation). Complete abortion refers to the expulsion of the entire fetus or fetuses, while incomplete abortion involves remnants of the fetus or gestational tissue remaining in the uterus.

**Why the Correct Answer is Right:** In this case, the ultrasound description of small grape-like cystic structures without evidence of a developing embryo indicates a situation where the gestational sac and fetal parts have been expelled, leaving only the placental tissue behind. This is a clinical manifestation of a molar pregnancy, a type of ectopic pregnancy characterized by the rapid growth of trophoblastic tissue due to a genetic abnormality in the fertilized ovum.

**Why Each Wrong Option is Incorrect:**

A. Ectopic pregnancy refers to pregnancy occurring outside the uterus, typically involving the fallopian tube. In this case, the ultrasound findings do not suggest an ectopic pregnancy.

B. Molar pregnancy, as described above, involves the rapid growth of trophoblastic tissue due to a genetic abnormality in the fertilized ovum. This option is correct, as it correlates with the ultrasound findings.

C. Incomplete abortion refers to the expulsion of a partially retained fetus or gestational tissue. In this scenario, the ultrasound shows the complete expulsion of the fetus or fetuses, making this option incorrect.

D. Chorioangioma is a benign tumor of the placenta, typically seen in the first trimester and does not result in the ultrasound findings described. This option is incorrect.

**Clinical Pearl:** Molar pregnancies are categorized into two types: complete and partial. Complete molar pregnancy (also known as a complete hydatidiform mole or choriocarcinoma) is a rare type of molar pregnancy where the entire fetus or gestational tissue is expelled, leading to the ultrasound findings described. This condition carries a high risk for choriocarcinoma, a type of gestational trophoblastic disease, due to the persistence of trophoblastic tissue. Regular follow-up and surveillance are crucial in these cases to monitor for progression to choriocarcinoma.