Chorionic villus sampling in the prenatal diagnosis of placental mesenchymal dysplasia

Complete Hydatidiform Mole with a Coexisting Viable Male Fetus Detected by Cell-Free DNA

Complete hydatidiform mole with coexisting fetus (CHMCF) is rare, and diagnosis is challenging due to limited data. Here, we present the case of a patient with noninvasive prenatal test (NIPT) resulting in "likely molar pregnancy" in the second trimester. Subsequent ultrasound confirmed a cystic appearing portion of the placenta. At 22 weeks, the patient delivered a demised fetus and two placentas. Pathology was consistent with CHMCF. This case is the first to show primary detection of a CHMCF with single-nucleotide polymorphism (SNP)-based NIPT prior to ultrasound identification. Our case suggests the use of SNP-based NIPT as an alternative noninvasive method to guide shared decision-making and clinical management for patients with this diagnosis.

Diagnosis and Management of Placental Mesenchymal Disease. A Review of the Literature

Objective

To review what is currently known about placental mesenchymal dysplasia (PMD) including imaging techniques for diagnosis and differentiation from a molar pregnancy, genetics, maternal/fetal effects, and management.

Evidence Acquisition

A literature search by research librarians at 2 universities was undertaken using the search engines PubMed and Web of Science. The search terms used were "etiology" OR "cause" OR "risk" OR "risks" OR "epidemiology" OR "diagnosis" OR "therapy" OR "prognosis" OR "management" AND "placental mesenchymal dysplasia" OR "placenta" AND "mesenchymal dysplasia." No limit was put on the number of years searched.

Results

The etiology of PMD remains uncertain, although there are a number of theories on causation. An elevated maternal serum α-fetoprotein level, slightly elevated human chorionic gonadotropin level, normal karyotype, multicystic lesions on ultrasound, and varying degrees of flow within cysts using color Doppler (stained-glass appearance) are helpful in making the diagnosis. On pathologic examination of the placenta, PMD is differentiated from molar pregnancy by the absence of trophoblastic hyperplasia. Fetal complications of PMD include hematologic disorders, Beckwith-Wiedemann syndrome, liver tumors, fetal growth restriction, preterm delivery, and intrauterine fetal demise. Maternal complications include gestational hypertension, preeclampsia, HELLP (hemolysis, elevated liver function tests, low platelets) syndrome, and eclampsia.

Conclusions

Accurate diagnosis of PMD is imperative for appropriate management and surveillance to minimize adverse maternal and fetal outcomes.

Relevance

The importance of a correct diagnosis of PMD is important because it can be misdiagnosed as a partial molar pregnancy or a complete mole with coexisting normal fetus, and this can result in inappropriate management.

Systematic review of sonographic findings of placental mesenchymal dysplasia and subsequent pregnancy outcome

OBJECTIVE

To describe the sonographic features and pregnancy outcomes of placental mesenchymal dysplasia (PMD), an entity often misdiagnosed as molar pregnancy.

METHODS

We reviewed PMD cases from our institution and performed a systematic review of the existing literature. Inclusion criteria for the review were diagnosis of PMD as defined by placental pathology, description of placental morphology on antenatal ultrasound and reporting of pregnancy outcomes.

RESULTS

We found three cases of PMD at our institution. Patient 1 had elevated human chorionic gonadotropin (hCG) and an enlarged, hydropic placenta at 13 weeks, suggestive of a molar pregnancy. Patient 2 also had elevated hCG with large, vascular placental lakes on ultrasound suggesting placenta accreta or molar pregnancy. Case 3 involved placentomegaly and fetal anomalies suggestive of Beckwith-Wiedemann syndrome. From the literature review, 61 cases met the inclusion criteria. The most common sonographic features included enlarged (50%) and cystic (80%) placenta with dilated chorionic vessels. Biochemical aneuploidy screening abnormalities were relatively common as were fetal anomalies, Beckwith-Wiedemann syndrome and other genetic abnormalities. Pregnancy complications included intrauterine growth restriction (IUGR; 33%), intrauterine fetal death (IUFD; 13%), and preterm labor (33%). Pregnancies without fetal anomalies, IUGR, IUFD or preterm labor had normal neonatal outcomes despite PMD (9%).

CONCLUSIONS

The differential diagnosis of PMD includes molar pregnancy and other placental vascular anomalies. PMD is associated with adverse pregnancy outcome, so heightened surveillance with genetic evaluation, serial growth scans and third-trimester assessment of wellbeing should be considered. PMD must be differentiated from gestational trophoblastic disease because management and outcomes differ.