Placental mesenchymal dysplasia associated with fetal aneuploidy

Placental mesenchymal disease masquerading as molar pregnancy with a favourable maternal and fetal outcome

Placental mesenchymal dysplasia (PMD) is an exceptionally rare placental anomaly characterised by placentomegaly and grape-like vesicles resembling partial mole on ultrasonography, yet it can coexist with a viable fetus. We present the case of a primigravida who presented at 22 weeks gestation with a suspected partial mole but with a normally growing fetus. The differential diagnoses considered included placental mesenchymal disease, partial mole and twin pregnancy with molar pregnancy. With normal beta HCG levels and prenatal invasive testing reports, a probable diagnosis of PMD was made, and after thorough counselling, the decision was made to continue the pregnancy. The pregnancy progressed until 37 weeks, culminating in the uneventful delivery of a 2.4 kg healthy male infant. Histopathology confirmed PMD. Early recognition and management of PMD pose significant challenges, given its rarity. Prenatal identification of PMD during both early and late gestation could avert unnecessary termination of pregnancy.

Placental Mesenchymal Dysplasia and Beckwith-Wiedemann Syndrome

Placental mesenchymal dysplasia (PMD) is characterized by placentomegaly, aneurysmally dilated chorionic plate vessels, thrombosis of the dilated vessels, and large grapelike vesicles, and is often mistaken for partial or complete hydatidiform mole with a coexisting normal fetus. Androgenetic/biparental mosaicism (ABM) has been found in many PMD cases. Beckwith-Wiedemann syndrome (BWS) is an imprinting disorder with complex and diverse phenotypes and an increased risk of developing embryonal tumors. There are five major causative alterations: loss of methylation of imprinting control region 2 (KCNQ1OT1:TSS-DMR) (ICR2-LOM), gain of methylation at ICR1 (H19/IGF2:IG-DMR) (ICR1-GOM), paternal uniparental disomy of 11 (pUPD11), loss-of-function variants of the CDKN1C gene, and paternal duplication of 11p15. Additional minor alterations include genetic variants within ICR1, paternal uniparental diploidy/biparental diploidy mosaicism (PUDM, also called ABM), and genetic variants of KCNQ1. ABM (PUDM) is found in both conditions, and approximately 20% of fetuses from PMD cases are BWS and vice versa, suggesting a molecular link. PMD and BWS share some molecular characteristics in some cases, but not in others. These findings raise questions concerning the timing of the occurrence of the molecularly abnormal cells during the postfertilization period and the effects of these abnormalities on cell fates after implantation.

Ultrasound and molecular prenatal diagnosis of Beckwith-Wiedemann syndrome: Two case reports

Beckwith-Wiedemann syndrome (BWS) is a rare genetic disease, characterized by macrosomia, congenital malformations and tumor predisposition, associated with genetic and epigenetic alterations in the 11p15 region. Most cases are diagnosed after birth, with prenatal diagnosis being difficult and depending on the identification of specific ultrasound anomalies, namely macrosomia, macroglossia, omphalocele and renal dysplasia. Case 1: Ultrasound diagnosis at 13 weeks of isolated omphalocele with normal array. At 20 weeks, there were shortened fetal long bones, foot deformity, macroglossia, corpus callosum hypoplasia and bilateral nephromegaly. Due to the polymalformative syndrome, a termination of pregnancy (TOP) was performed. The anatomopathological study of the placenta identified mesenchymal dysplasia. The search for the methylation pattern of the 11p15 region by MS-MLPA was normal and the molecular study of the CDKN1C gene identified a likely pathogenic variant, inherited from the mother. Case 2: Morphological ultrasound at 21 weeks revealed macrosomia, macroglossia, omphalocele, bilateral renal dysplasia, and hydramnios. The cytogenetic study, after amniocentesis, was normal (46,XX karyotype). TOP was performed. The anatomopathological study of the fetus confirmed the described malformations and the one concerning the placenta identified placentomegaly. The search for the methylation pattern of the 11p15 region by MS-MLPA revealed abnormal methylation. These results confirmed the diagnosis of BWS in both cases. Prenatal ultrasound suspicion of this pathology is extremely important to guide the conduct in pregnancy and/or the prevention of perinatal complications. Shortened fetal long bones and foot deformity complement the broad spectrum of this syndrome. Positive molecular tests allow confirming the diagnosis, assessing the risk of recurrence and guiding the surveillance of future pregnancy.

Localized Placental Mesenchymal Dysplasia in Monochorionic Diamniotic Twin Placenta with Beckwith-Wiedemann Syndrome

IntroductionPlacental mesenchymal dysplasia (PMD) is often associated with Beckwith-Wiedemann syndrome. Case report: A 27-year-old woman with preeclampsia prematurely delivered twin girls. One side of the placenta was larger with numerous grape-like vesicles, histologically with large, cystic, stem villi with cisterns without syncytiotrophoblastic hyperplasia. This side showed mosaicism for chromosome 11 by FISH and hypomethylation at ICR2 by MLPA. The smaller side of the placenta was normal macroscopically, microscopically, and karyotypically. There was symmetric growth restriction, macroglossia and hypoglycemia of the girl corresponding to the abnormal placental side, and lesser symmetric growth restriction and mild hypoglycemia in the other girl. Conclusion: Localized placental mesenchymal dysplasia can occur in monochorionic diamniotic twin placenta with Beckwith-Wiedemann syndrome. Fetal affects may be asymmetric. PMD can be associated with mosaicism monosomy of chromosome 11.

A Challenging Diagnosis: Placental Mesenchymal Dysplasia—Literature Review and Case Report

We describe a 22-year-old woman (2-gravid) case who was referred to our clinic at 18 weeks of gestation for a placenta with vesicular lesions discovered on prenatal examination routine. An ultrasound exam at 31 weeks of gestation showed numerous vesicular lesions, which gradually augmented as the pregnancy advanced. A live normal-appearing fetus was confirmed by intrauterine growth restriction (IUGR). The maternal serum β-human chorionic gonadotropin level remained in normal ranges. At some point, a multidisciplinary medical consensus considered the termination of the pregnancy, but the patient refused to comply. At 33 weeks of gestation, preterm premature rupture of membranes (pPROM) occurred, and she spontaneously delivered a 1600 g healthy female baby with a good long-term outcome. Placental mesenchymal dysplasia (PMD) was retrospectively diagnosed after confronting the data from ultrasound, chorionic villus sampling (CVS), amniocentesis, pathological examination, and immunohistochemical stain. The lack of sufficient reports of PMD determines doctors to be cautious and reserved, approaching these cases more radically than necessary. We reviewed this disease and searched for all cases of PMD associated with healthy, live newborns.

Complete Molar Pregnancies with a Coexisting Fetus: Pregnancy Outcomes and Review of Literature

Objective  The objective of the study was to review the obstetric outcomes of complete hydatidiform molar pregnancies with a coexisting fetus (CHMCF), a rare clinical entity that is not well described. Materials and Methods  We performed a retrospective case series with pathology-confirmed HMCF. The cases were collected via solicitation through a private maternal-fetal medicine physician group on social media. Each contributing institution from across the United States ( n  = 9) obtained written informed consent from the patients directly, obtained institutional data transfer agreements as required, and transmitted the data using a Health Insurance Portability and Accountability Act of 1996 (HIPAA) compliant modality. Data collected included maternal, fetal/genetic, placental, and delivery characteristics. For descriptive analysis, continuous variables were reported as median with standard deviation and range. Results  Nine institutions contributed to the 14 cases collected. Nine (64%) cases of CHMCF were a product of assisted reproductive technology and one case was trizygotic. The median gestational age at diagnosis was 12 weeks and 2 days (9 weeks-19 weeks and 4 days), and over half were diagnosed in the first trimester. The median human chorionic gonadotropin (hCG) at diagnosis was 355,494 mIU/mL (49,770-700,486 mIU/mL). Placental mass size universally enlarged over the surveillance period. When invasive testing was performed, insufficient sample or no growth was noted in 40% of the sampled cases. Antenatal complications occurred in all delivered patients, with postpartum hemorrhage (71%) and hypertensive disorders of pregnancy (29%) being the most frequent outcomes. Delivery outcomes were variable. Four patients developed gestational trophoblastic neoplasia. Conclusion  This series is the largest report of obstetric outcomes for CHMCF to date and highlights the need to counsel patients about the severe maternal and fetal complications in continuing pregnancies, including progression to gestational trophoblastic neoplastic disease. Key Points CHMCF is a rare obstetric complication and may be associated with the use of assisted reproductive technology.Universally, patients with CHMCF who elected to manage expectantly developed antenatal complications.The risk of developing gestational trophoblastic neoplasia after CHMCF is high, and termination of the pregnancy did not decrease this risk.

Sudden fetal death with placental mesenchymal dysplasia complicated by placenta previa

Placental mesenchymal dysplasia (PMD) is a rare placental abnormality that is closely related to severe pregnancy complications. A 27-year-old woman with fetal growth restriction and placenta previa was referred to a university hospital at 22 gestational weeks (GW). She was suspected of having a twin pregnancy with a complete or partial hydatidiform mole and coexisting normal live fetus, because two separate placentas, an enlarged one with multiple cystic lesions and a normal one, were shown on ultrasound examinations. At 27 GW, she experienced a sudden intrauterine fetal death (IUFD) after bleeding due to placenta previa, despite confirmation of fetal well-being at 2 h before bleeding. After delivery, histopathological examination confirmed the diagnosis of PMD. This is the first documented case of a woman with PMD and placenta previa who had a sudden IUFD after bleeding. Patients with both PMD and placenta previa should be considered at extremely high risk for IUFD.

Placental mesenchymal dysplasia: What every radiologist needs to know

Placental mesenchymal dysplasia (PMD) is an uncommon vascular anomaly of the placenta characterized by placentomegaly with multicystic placental lesion on ultrasonography and mesenchymal stem villous hyperplasia on histopathology. Placental mesenchymal dysplasia should be considered in the differential diagnosis of cases of multicystic placental lesion such as molar pregnancy, chorioangioma, subchorionic hematoma, and spontaneous abortion with hydropic placental changes. However, lack of high-velocity signals inside the lesion and a normal karyotype favor a diagnosis of PMD. PMD must be differentiated from gestational trophoblastic disease because management and outcomes differ. We report the case of an 18-year-old female at 15 weeks of gestation with sonographic findings suggestive of placental mesenchymal dysplasia. The diagnosis was confirmed on histopathology.

Differentiating complete hydatidiform mole and coexistent fetus and placental mesenchymal dysplasia: A series of 9 cases and review of the literature

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Twin mole and placental mesenchymal dysplasia are set apart by patient symptoms, labs, and imaging.

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Continuing with a twin mole pregnancy does not appear to increase the risk of GTN.

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Twin mole pregnancy does carry an increased risk of miscarriage and pre-term labor.

To identify the differentiating features in clinical presentation, management, and maternal/fetal outcome in complete hydatidiform mole and coexistent fetus compared with placental mesenchymal dysplasia.

Between 1997 and 2015, five women with complete hydatidiform mole and coexistent fetus and four women with placental mesenchymal dysplasia were managed at the University of California San Francisco. Clinical features were analyzed and compared with previously published data.

Of the five cases of complete hydatidiform mole and coexistent fetus, two had live births. β-hCG levels were > 200,000 IU/L in all cases. On imaging, a clear plane between the cystic component and the placenta favored a diagnosis of complete hydatidiform mole and coexistent fetus. None of the patients went on to develop gestational trophoblastic neoplasia (GTN), with a range of follow-up from 2 to 38 months. Combining this data with previously published work, the live birth rate in these cases was 38.8%, the rate of persistent GTN was 36.2%, and the rate of persistent GTN in patients with reported live births was 27%. Of the four cases of placental mesenchymal dysplasia, all four had live births. One patient developed HELLP syndrome and intrauterine growth restriction; the remaining three were asymptomatic.

Maternal symptoms, fetal anomalies, β-hCG level, and placental growth pattern on imaging may help differentiate between complete hydatidiform mole and coexistent fetus and placental mesenchymal dysplasia. There was not an increased risk of gestational trophoblastic neoplasia in patients with complete hydatidiform mole and coexistent fetus who opted to continue with pregnancy.

Variants in Maternal Effect Genes and Relaxed Imprinting Control in a Special Placental Mesenchymal Dysplasia Case with Mild Trophoblast Hyperplasia

Placental mesenchymal dysplasia (PMD) and partial hydatidiform mole (PHM) placentas share similar characteristics, such as placental overgrowth and grape-like placental tissues. Distinguishing PMD from PHM is critical because the former can result in normal birth, while the latter diagnosis will lead to artificial abortion. Aneuploidy and altered dosage of imprinted gene expression are implicated in the pathogenesis of PHM and also some of the PMD cases. Diandric triploidy is the main cause of PHM, whereas mosaic diploid androgenetic cells in the placental tissue have been associated with the formation of PMD. Here, we report a very special PMD case also presenting with trophoblast hyperplasia phenotype, which is a hallmark of PHM. This PMD placenta has a normal biparental diploid karyotype and is functionally sufficient to support normal fetal growth. We took advantage of this unique case to further dissected the potential common etiology between these two diseases. We show that the differentially methylated region (DMR) at NESP55, a secondary DMR residing in the GNAS locus, is significantly hypermethylated in the PMD placenta. Furthermore, we found heterozygous mutations in NLRP2 and homozygous variants in NLRP7 in the mother’s genome. NLRP2 and NLRP7 are known maternal effect genes, and their mutation in pregnant females affects fetal development. The variants/mutations in both genes have been associated with imprinting defects in mole formation and potentially contributed to the mild abnormal imprinting observed in this case. Finally, we identified heterozygous mutations in the X-linked ATRX gene, a known maternal–zygotic imprinting regulator in the patient. Overall, our study demonstrates that PMD and PHM may share overlapping etiologies with the defective/relaxed dosage control of imprinted genes, representing two extreme ends of a spectrum.

Incidental diagnosis of sad fetus syndrome in triplets

An unusual presentation of gestational trophoblastic disease is twin molar pregnancy, rarest in triplets with differentials being partial/complete mole, placental mesenchymal dysplasia (PMD), placental cysts or chorioangioma each with different complications. Counselling to continue pregnancy depends on diagnosis. A 37-year-old G₂P₁L₁, donor oocyte In vitro fertlisation (IVF) twin pregnancy was referred at 24 weeks with cystic areas in placenta. Probability of twin partial mole or PMD was assessed. The scan of fetuses showed normal growth, no structural anomalies. Biochemical markers showed high maternal beta human chorionic gonadotropin (β-hCG). Amniocentesis of molar fetus revealed normal karyotype. Likely diagnosis made as twin partial mole. The patient delivered by caesarean section at 28⁺² weeks due to preterm labour. Twins, a male and a female baby, were delivered with three placentas, two normal and the third with molar changes and no fetal parts. Diagnosis was revised as triplet with partial mole, which was confirmed on histopathology. Serial monitoring of β-hCG became undetectable by eighth week. The male baby died on day 4. The mother and the female baby were discharged.

Recurrent GTD and GTD coexisting with normal twin pregnancy

Hydatidiform mole (HM) affects around 1/1000 pregnancies, and in such cases the recurrence risk is around 1%, being greater for those with complete HM (CHM). Whilst most cases appear sporadic with unknown mechanisms, there is a distinct subgroup of patients who suffer recurrent pregnancy loss, including multiple recurrent CHM (familial recurrent biparental HM syndrome). The majority of these cases are related to maternal genetic mutations in genes related to the control of imprinting, specifically NALP7 and KHDC3L. Oocyte donation is an effective treatment allowing these patients to have successful pregnancies. Approximately 1 in 50,000 pregnancies are complicated by twin pregnancy comprising normal foetus and HM, the majority of reported cases being CHM. Such pregnancies are at significantly increased risk of complications, including pregnancy loss, early-onset preeclampsia and severe preterm delivery, but when managed conservatively the delivery of a liveborn healthy infant occurs in around one-third of cases. Regardless of management, the risk of persistent GTD in such cases appears similar to that following singleton CHM. Rarely, other conditions mimic prenatal ultrasound appearances of twin pregnancy with HM, CHM mosaicism and placental mesenchymal dysplasia, both of which have distinctive histological and genetic features.

Prenatal features in Beckwith-Wiedemann syndrome and indications for prenatal testing

BACKGROUND

Most cases of Beckwith-Wiedemann spectrum (BWSp) are diagnosed after birth and few studies evaluated the prenatal phenotype; here, we investigate these aspects in a large series of patients with BWSp.

METHODS

Eighty-nine patients with BWSp recruited through the BWSp Internal Registry of the Pediatric Genetics Unit of the Regina Margherita Children's Hospital of Torino and through the Italian Association of Patients with BWSp. Data collection was conducted through administration of a personalised questionnaire, interview to patients' parents, review of the clinical records, including prenatal ultrasound (US) and biochemical screening tests, physical examination and review of clinical and molecular data of the patients.

RESULTS

Seventeen patients (19.1%) were conceived through assisted reproductive techniques (ART). Twinning occurred in nine pregnancies (three from ART). Pregnancy biochemical screening tests showed increased alpha-fetoprotein (1.52±0.79 multiples of median (MoM), p=0.001), uEstriol (1.37±0.38 MoM, p<0.001) and total human chorionic gonadotrophin (2.14±2.12 MoM, p=0.008) at 15-18 weeks (n=28). Morphology US scan revealed abdominal and head circumferences higher than normal (1.42±1.10 SD scores, p<0.001 and 0.54±0.88, p<0.001, respectively) with normal femur lengths. Sixty-four cases (71.9%%) had a various combination of US findings, including macrosomia (n=32), omphalocele (n=15), enlargement of abdominal organs (n=6), macroglossia (n=11), adrenal cysts/masses (n=2), nephroureteral anomalies (n=11), polyhydramnios (n=28), placental enlargement (n=2) or mesenchymal dysplasia (n=4).

CONCLUSION

We propose a clinical scoring system for prenatal molecular investigations defining major, minor and supportive criteria among the several features often observed prenatally in BWSp.

Vesicules or placental lakes in ultrasonography, determining the correct etiology

The prenatal examination of the placenta is often an afterthought to that of the fetus in ultrasonography. Not giving the placenta its due may however result in potentially serious placental pathologies remaining undiscovered, notably in the presence of anechoic zones. These latter have earned numerous names, including "placental lakes", "placental venous lakes", "placental lacunae" or "placental caverns" among others, but they have received little attention in the literature. We thus feel that it is essential to review the various pathologies that placental lakes may signal, since any one of them may greatly affect patient management. The difficulty resides in the diversity of these pathologies, sometimes oncological, other times fetal, and in the potential need for multidisciplinary surgery. Some of these causes of placental lakes may result in maternal or fetal complications and/or necessitate increased and casespecific surveillance. The diagnosis and treatment of such cases requires close collaboration between sonographers, obstetricians, geneticists and pathologists. The work we present here focuses on the different etiologies to consider in the presence of a lacunar placenta and the necessary diagnostic measures. Our objective is to propose a diagnostic flowchart to aid clinicians in this dense differential 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.

Mosaic paternal haploidy in a patient with pancreatoblastoma and Beckwith-Wiedemann spectrum

Pancreatoblastoma is a rare type of pancreatic cancer in children. Here, we describe a case in which Beckwith-Wiedemann syndrome (BWS) was first suspected because of placental mesenchymal dysplasia. Although the baby did not show the stigmata characteristic of BWS or abnormal peripheral blood methylation, she developed a massive pancreatoblastoma 2 months later. She survived after partial excision of the tumor and chemotherapy. The methylation pattern of the pancreatoblastoma tissue was typical of BWS. Single nucleotide polymorphism (SNP) array analyzes revealed that the pancreatoblastoma tissue had genome-wide loss of maternal alleles. Peripheral blood and nontumor pancreatic tissue showed normal biparental genomic contribution. Interphase fluorescence in situ hybridization analysis with centromeric probes for chromosomes 2 and 11 revealed haploid pancreatoblastoma cells, whereas the placental mesenchymal dysplasia tissue and nontumor pancreas tissue showed diploidy. SNP genotype analysis suggested the presence of mosaicism with the pancreatoblastoma tissue having a different paternal haplotype than that of the peripheral blood and nontumor pancreatic tissue. We report for the first time mosaic paternal haploidy associated with pancreatoblastoma. Babies with placental mesenchymal dysplasia, even those without a definitive diagnosis of BWS, need to be closely followed for the occurrence of embryonic tumors.

A case report of placental mesenchymal dysplasia: A rare case of a genetically normal fetus with severe intrauterine growth restriction

RATIONALE

We report a rare case of a pregnant woman with placental mesenchymal dysplasia (PMD) and intrauterine growth restriction (IUGR) with a genetically normal fetus.

PATIENT CONCERNS

A 42-year-old woman Gravida I, Para I with pre-existent uncontrolled hypertension and uterine polyfibromatosis present at 30 weeks of gestation for diminished fetal activity during the last 2 days.

DIAGNOSIS

Placental mesenchymal dysplasia associated with intrauterine growth restriction, hypertension, and uterine polyfibromatosis.

INTERVENTION

A live male infant was delivered by emergency caesarean section.

OUTCOMES

The infant, weighing 700 g, died 4 days after birth due to a massive intracerebral hemorrhage.

LESSONS

A careful examination should be done at every ultrasound in case of a fetus with IUGR to exclude some rare cases of placental pathologies. PMD can be a rare cause of IUGR with a genetically normal fetus.

Placental mesenchymal dysplasia: An underdiagnosed placental pathology with various clinical outcomes

BACKGROUND

Placental mesenchymal dysplasia (PMD) is a rare vascular and connective placental anomaly, which is often associated with severe fetal and/or maternal complications. The diversity of presentation of PMD challenges diagnosis and effective pregnancy management.

OBJECTIVE

We aimed to review cases presenting at 7 tertiary centers worldwide over the last decade and to study the occurrence of obstetric and neonatal complications.

STUDY DESIGN

Pathology databases from 7 tertiary hospitals were screened for cases of PMD (between 2007-2017). Pregnancy history, outcomes and ultrasound images were then reviewed for each case.

RESULTS

Twenty-two cases of PMD were identified. Mean gestational age at diagnosis was 23 weeks (16-39 weeks). Prenatal biochemical screening was abnormal in 8 cases (36%). Of the 12 cases that underwent invasive genetic testing, 4 were abnormal. Six patients (27%) developed maternal complications (preeclampsia/gestational hypertension). Fetal growth restriction was identified in 11 cases (50%) and fetal death in 4 (18%). Four (18%) pregnancies were terminated, 9/14 (64%) delivered preterm and only three (14%) progressed normally. Fourteen babies were born alive; 5 (35%) died in the first sixty-one days after birth, 5 (35%) had transient thrombopenia and 1 (7%) had developmental delay at last follow-up. Our series identified four potential new associations with PMD: placental triploidy mosaicism, CHARGE syndrome, fetal pleuropulmonary blastoma and fetal skeletal dysplasia.

CONCLUSIONS

PMD was substantially under-diagnosed before delivery in this cohort. Sonographers, fetal medicine specialists, obstetricians and pathologists should all suspect PMD in cases of an enlarged placenta and should look for fetal abnormalities. Diagnostic genetic testing should be discussed to exclude partial molar pregnancy. Close pregnancy follow-up is indicated due to the high risk of associated fetal or maternal adverse outcomes.

Placental Pathology in Placental Mesenchymal Dysplasia with 13q12.11 Deletion and a 25-Week Gestation Female Infant

Patient: —

Final Diagnosis: Placental mesenchymal dysplasia

Symptoms: Premature rupture of membranes

Medication:—

Clinical Procedure: Amniocentesis

Specialty: Obstetrics and Gynecology

Placental examination: prognosis after delivery of the growth-restricted fetus

PURPOSE OF REVIEW

This article describes the role of placental examination in the prognostic evaluation of fetal growth restriction (FGR) infants.

RECENT FINDINGS

A new comprehensive placental classification system was reported. Maternal underperfusion, fetal thrombotic vasculopathy (FTV), villitis (including villitis of unknown etiology and infectious villitis), inflammation, and immature/dysmature villi are important factors affecting FGR prognosis, whereas genomic imprinting is a key factor affecting growth and diseases, as well as placental abnormality.

SUMMARY

We discuss the role of placental examination in determining FGR prognosis. Maternal underperfusion, fetal thrombotic vasculopathy, and villitis (including villitis of unknown etiology and infectious villitis) are the most important findings affecting FGR prognosis. Although limited, data have suggested an association of inflammation and immature/dysmature villi with postnatal growth in FGR infants. Placental size also contributes postnatally through fetal programming. In addition, placental imprinting can be a key of pre and postnatal growth and diseases, including imprinting disorders, as well as placental abnormalities such as placental mesenchymal dysplasia.

Multimodality imaging of placental masses: a pictorial review

Placental masses are uncommonly identified at the time of obstetric ultrasound evaluation. Understanding the pathologies presenting as placental masses is key for providing a differential diagnosis and guiding subsequent management, which may include additional imaging with magnetic resonance (MR) imaging. Potential benign entities include chorioangiomas and teratomas. Larger chorioangiomas can cause fetal cardiovascular issues from volume overload. Placental mesenchymal dysplasia has an association with fetal anomalies and detailed fetal evaluation should be performed when it is suspected. Identifying other cystic masses such as partial and complete moles is crucial to prevent erroneous pregnancy termination. This review addresses normal imaging appearance of the placenta on ultrasound and MR imaging and describes various trophoblastic and nontrophoblastic placental masses. Potential placental mass mimics including uterine contractions and thrombo-hematomas are also presented.

Placental mesenchymal dysplasia: a rare clinicopathologic entity confused with molar pregnancy

Placental mesenchymal dysplasia (PMD) is a rare placental abnormality characterised by placentomegaly and grape-like vesicles resembling partial mole by ultrasonography, but in contrast to partial mole can co-exist with a viable fetus. Although the karyotype is normal, the fetus is at increased risk for intrauterine growth restriction, intrauterine fetal demise or perinatal death and Beckwith-Wiedemann syndrome. Prenatal diagnosis is difficult and the final diagnosis is usually achieved by postpartum histological examination of the placenta. We present two recent cases of placental mesenchymal dysplasia with poor obstetric outcome. One fetus presented with reduced growth parameters, while the other fetus showed hepatosplenomegaly and early hydropic changes that appear to be associated with Beckwith-Wiedemann syndrome. In this report, the clinico-pathological features of two cases of PMD are discussed and the differentiation from a partial mole is highlighted. This study also supports the utility of cytogenetic ploidy analysis and p57KIP2 protein staining in the evaluation of pregnancies with PMD.

A case of placental mesenchymal dysplasia

Placental mesenchymal dysplasia (PMD) rarely complicates with pregnancy. A 30-year-old woman, gravida 3, para 3, presenting with placentomegaly, was referred to our department at 18 weeks of gestation. An ultrasonography revealed a normal fetus with a large multicystic placenta, measuring 125 × 42 × 80 mm. The border between the lesion and normal region was not clear. Color doppler revealed little blood flow in the lesion. Magnetic resonance imaging revealed normal fetus and a large multicystic placenta. Serum human chorionic gonadotropin level was 20124.97 U/L, which was normal at 20 weeks of gestation. Thus, placental mesenchymal dysplasia rather than hydatidiform mole with coexistent fetus was suspected. Then, routine checkup was continued. Because she had the history of Cesarean section, an elective Cesarean section was performed at 37 weeks of gestation, and 2520 g female infant with apgar score 8/9 was delivered. The baby was normal with no evidence of Beckwith-Wiedemann syndrome. Placenta of 20 × 16 × 2 cm, weighing 720 g, was bulky with grape like vesicles involving whole placenta. Microscopic examination revealed dilated villi and vessels with thick wall which was lacking trophoblast proliferation. Large hydropic stem villi with myxomatous struma and cistern formation were seen. PMD was histopathologically confirmed.

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.

Placental mesenchymal dysplasia

Placental mesenchymal dysplasia is a benign condition that can be confused with a molar pregnancy by ultrasound scanning and gross examination. Conservative management should be considered with a normal-appearing singleton fetus and a cystic-appearing placenta. We present a case of placental mesenchymal dysplasia with a favorable outcome.

Partial molar pregnancy with a chromosomically and phenotypically normal embryo: presentation of an extremely rare case and review of literature

We present an extremely rare case of partial molar pregnancy with a chromosomically and phenotypically normal embryo and review of the literature. A 31-year-old nulliparous was referred to us at 30 weeks of gestation due to absence of fetal movements and subsequent ultrasound examination revealed intrauterine demise. Prenatal amniocentesis due to raised maternal serum α-fetoprotein had shown a karyotypically normal female embryo and second trimester ultrasound demonstrated no anatomic abnormalities. Upon induction of labor with misoprostol, a phenotypically normal embryo was delivered and the placenta showed intermixed areas of marked hydatidiform villous change and normal parenchyma. Pathologic examination of the placenta confirmed the molar change of placenta. Two are the main theories discussed herein that explain the placental molar changes in singleton pregnancies: confined placental mosaicism (one case reported to date) and placental mesenchymal dysplasia (70 cases reported). Differential diagnosis is based on histopathologic features and genetic analysis of placenta.

Dizygotic twin pregnancy with a normal fetus and a nodular embryo associated with a partial hydatidiform mole

Although twin pregnancies complicated by a coexisting complete hydatidiform mole are uncommon, those with partial hydatidiform mole (PHM) are exceedingly rare; there are only several well-documented cases diagnosed antenatally. Here we present the first case of a twin placenta containing a nodular embryo associated with PHM diagnosed on routine placental examination. This dizygotic twin pregnancy featured viable embryos at 8 weeks' gestation, death of 1 embryo at 12 weeks, and delivery of a healthy infant by caesarean section at 28 weeks because of worsening maternal reflux nephropathy. Macroscopic and microscopic placental examination and fluorescence in situ hybridization showed one part of the placenta to be diploid and the other to contain a vanishing triploid embryo and a PHM, which had eluded antenatal ultrasound diagnosis. Careful pathologic examination of vanishing twins and their placentas may disclose an unexpected PHM, which can be associated, albeit infrequently, with persistent gestational trophoblastic disease or a trophoblastic tumor.

Abnormal villous morphology associated with triple trisomy of paternal origin

The vast majority of trisomies in spontaneous abortions (SAB) are single and of maternal origin, most frequently due to meiosis I errors. Triple trisomies are exceedingly rare (approximately 0.05% of spontaneous abortions), most often of maternal origin, and associated with increased maternal age. Some trisomic SAB specimens can exhibit abnormal villous morphology simulating a partial hydatidiform mole, a distinct form of hydatidiform mole characterized by diandric triploidy. A SAB specimen from a 27-year-old woman, G1P0 at 8 weeks gestational age, was reviewed in consultation to address the finding of morphological features suggestive of a partial hydatidiform mole but DNA ploidy analysis yielding a diploid result. The villi were irregularly shaped and hydropic but lacked trophoblastic hyperplasia; p57 expression was retained. Since fully developed features of a partial hydatidiform mole were lacking, additional analysis was performed. Molecular genotyping and single nucleotide polymorphism array analysis demonstrated biparental diploidy with trisomy of chromosomes 7, 13, and 20, all of paternal origin. The three trisomies may have originated from paternal meiosis II errors, or from mitotic nondisjunction. We believe this to be the first report of triple trisomy in a SAB confirmed to be of paternal origin.

Placental mesenchymal dysplasia associated with hepatic and pulmonary hamartoma

This report describes a 31-week stillborn female infant with placental mesenchymal dysplasia (PMD) in association with hepatic mesenchymal hamartoma (HMH) and pulmonary hamartoma. Placental mesenchymal dysplasia was initially misdiagnosed as a partial mole. However, histologically, no trophoblastic proliferation or inclusions were observed. Differential diagnosis of the hepatic mass with similar tumors is discussed. To our knowledge, this is the first case of lung hamartoma reported in a fetus and the first case related to PMD and HMH. A common anomalous development of the mesoderm, a reparative post-injury process and a genetic mechanism, have been proposed to explain their pathogenesis.

Three-dimensional sonography of placental mesenchymal dysplasia and its differential diagnosis

OBJECTIVE

Placental mesenchymal dysplasia (PMD) is an uncommon vascular anomaly of the placenta characterized by mesenchymal stem villous hyperplasia. Its main sonographic feature is a thickened placenta with hypoechoic areas, and an accurate sonographic diagnosis is challenging. The aim of this study was to report 2 cases of PMD and discuss the differential diagnosis of its sonographic features.

METHODS

Cases of placental masses were studied by 2-dimensional (2D), 3-dimensional (3D), and color Doppler imaging.

RESULTS

In case 1, a thick placenta with multiple hypoechoic areas was noted at 13 weeks' gestation. At 19 weeks, the multicystic area, clearly demarcated from a normal-looking placenta, measured 6.5 x 8.5 cm and enlarged gradually. The patient gave birth to a 625-g female neonate after spontaneous labor at almost 26 weeks' gestation. In case 2, a first sonographic examination at 25 weeks' gestation revealed a thickened placenta with hypoechoic areas and a fetus with a single umbilical artery and a ventricular septal defect. At 27 weeks, the abnormal area of the placenta measured 14.5 x 7.5 cm. At 32 weeks' gestation, a caesarean delivery was performed because of a nonreassuring fetal heart tracing, and a 1415-g female neonate was delivered. Both cases were evaluated by 2D, 3D, and color Doppler imaging, and the pathologic features of both placentas were consistent with PMD.

CONCLUSIONS

Placental mesenchymal dysplasia should be considered in the differential diagnosis of every placental mass, especially in cases of multicystic placental lesion with lack of high-velocity signals inside the lesion, and a normal karyotype.

Placental mesenchymal dysplasia associated with trisomy 13: sonographic findings

Placental mesenchymal dysplasia (PMD) is a rare placental abnormality with sonographic and macroscopic features similar to those seen in a partial hydatidiform mole, and which has usually been reported with a normal female karyotype. We report a case of prenatally suspected PMD associated with trisomy 13. Sonography performed at 17 weeks' gestation showed multiple cystic spaces in the placenta resembling molar tissue, and a fetus with postaxial polydactyly and an atrial septal defect. An amniocentesis revealed a fetal karyotype of 46,XY,der(13), t(13;13)(q11;q11)[20]/47,XY,+13[11], consistent with trisomy 13. Cordocentesis confirmed the cytogenetic diagnosis. Histopathologic examination of the placenta following termination of the pregnancy at 22 weeks' gestation showed enlarged stem villi with loose connective tissue and cistern formation and no evidence of trophoblastic hyperplasia or stromal trophoblastic inclusions, which was consistent with PMD. PMD should be considered in the differential diagnoses of a placenta showing multiple cystic lesions on prenatal sonography, and karyotypic analysis should be performed.