Placental mesenchymal dysplasia differentially diagnosed from molar pregnancy by 3‐D inversion mode rendering: A case report

Abstract

Placental mesenchymal dysplasia (PMD) is a rare placental vascular anomaly which resembles partial molar pregnancy by 2-D ultrasonography. It is challenging but clinically important to distinguish between them in order to avoid unnecessary termination of pregnancy. A patient was referred to our centre at 13 weeks of gestation and 2-D ultrasound of the placenta showed a widespread vesicular pattern mixed with normal appearing placenta. Amniotic fluid volume was normal, and the fetus appeared to be an appropriate size for gestation without obvious structural abnormalities. 3-D reconstruction imaging of the placenta showed a large multi-cystic area arising from the chorionic plate which was adjacent to normal-appearing placenta. 3-D imaging rendered with 'inversion mode' revealed multiple fluid-filled structures with different sizes and appearances. Her serum hCG level was slightly elevated. All findings taken together, we suspected PMD rather than partial molar pregnancy. Histological examinations of the placenta after termination at 15 weeks confirmed the diagnosis.

Placental mesenchymal dysplasia vs molar pregnancy: A case report

“…Based on the abnormal appearance of the placenta, the initial differential diagnoses included a chromosomal abnormality, marginal haemorrhage with cystic degeneration, possible twin pregnancy with complete mole, and coexisting fetus or partial molar pregnancy . The latter seemed unlikely in view of the normal fetus.…”

“…At 31 weeks gestation, a new finding of tortuous distended vessels on the surface of the abnormal placenta were noted. These appearances were believed to be placental surface varices, possibly either an arteriovascular malformation or placenta chorioangioma (Figure ) . The most likely diagnosis was PMD, with the differential diagnoses being chorioangioma or molar pregnancy …”

“…PMD features placental hypertrophy, with grape‐like fluid‐filled spaces that can easily be misdiagnosed for other conditions, particularly molar pregnancy. It can be difficult to differentiate these entities with ultrasound alone; however, it is very important for sonographers to understand the difference between PMD and molar pregnancy as each have a very different prognosis …”

“…Despite similar appearances, unlike a molar pregnancy, a fetus can coexist with PMD . This highlights the importance of early recognition and correct diagnosis to ensure unnecessary termination of what resembles maternal trophoblastic disease (molar pregnancy) .…”

“…PMD is not without its complications and is most commonly associated with fetal growth restriction (FGR), preterm delivery, Beckwith‐Wiedemann Syndrome (BWS) and intrauterine fetal death (IUFD). In rare cases, fetal blood and liver disorders have also been reported …”