CEUSP. Valencia. Venezuela.

Case report
The following images show a case of partial molar pregnancy with normal diploid fetus. The mother was an 18-year-old primigravida presented to our department at 17 weeks of pregnancy. Ultrasonographic examination showed normal fetal morphology and biometry corresponding to the presumed gestational age. The placenta was enlarged with multiple cystic structures resembling structure of a honeycomb. Partial hydatidiform mole was suspected, but the patient refused invasive testing and opted for the continuation of the pregnancy.

Series of ultrasonographic examinations was performed at 19, 24, 31, and 36 weeks of pregnancy. Intrauterine growth retardation was observed during the rest of the pregnancy. The placenta stayed without changes. The baby was born via cesarean section at 36 weeks (female, 1900 g). Postpartum adaptation of the newborn was good. The placenta showed multiple hydropic villi and cystic structures and hydatid mole was confirmed.

HCG levels of the mother had gradually decreased and no signs of persistent trophoblastic disease were observed.

The combination of the molar pregnancy and normal diploid fetus is rare and can be explained by confined placental mosaicism [1] or a twin pregnancy where the other conceptus has degenerated into a mole [2]. Another possibility that should be taken into consideration in cases of enlarged cystic placenta and intrauterine growth restriction of the fetus is placental mesenchymal dysplasia.

Following images show series of findings obtained from 17 to 36 weeks. Normal fetal morphology and molar changes of the placenta (honeycomb appearance) can be seen.

1. Sarno AP Jr, Moorman AJ, Kalousek DK. Partial molar pregnancy with fetal survival: an unusual example of confined placental mosaicism. Obstet Gynecol. 1993 Oct;82(4 Pt 2 Suppl):716-9. PubMed PMID: 8378025.

2. Chen FP. Molar pregnancy and living normal fetus coexisting until term: prenatal biochemical and sonographic diagnosis. Hum Reprod. 1997 Apr;12(4):853-6. PubMed PMID: 9159456.