Pregnancy with concomitant chorangioma and placental vascular malformation with mesenchymal hyperplasia

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.

Aberrant hypomethylation at imprinted differentially methylated regions is involved in biparental placental mesenchymal dysplasia

BACKGROUND

Placental mesenchymal dysplasia (PMD) is a morphological abnormality resembling partial hydatidiform moles. It is often associated with androgenetic/biparental mosaicism (ABM) and complicated by Beckwith-Wiedemann syndrome (BWS), an imprinting disorder. These phenomena suggest an association between PMD and aberrant genomic imprinting, particularly of CDKN1C and IGF2. The existence of another type of PMD containing the biparental genome has been reported. However, the frequency and etiology of biparental PMD are not yet fully understood.

RESULTS

We examined 44 placental specimens from 26 patients with PMD: 19 of these were macroscopically normal and 25 exhibited macroscopic PMD. Genotyping by DNA microarray or short tandem repeat analysis revealed that approximately 35% of the macroscopic PMD specimens could be classified as biparental, while the remainder were ABM. We performed a DNA methylation analysis using bisulfite pyrosequencing of 15 placenta-specific imprinted differentially methylated regions (DMRs) and 36 ubiquitous imprinted DMRs. As expected, most DMRs in the macroscopic PMD specimens with ABM exhibited the paternal epigenotype. Importantly, the biparental macroscopic PMD specimens exhibited frequent aberrant hypomethylation at seven of the placenta-specific DMRs. Allelic expression analysis using single-nucleotide polymorphisms revealed that five imprinted genes associated with these aberrantly hypomethylated DMRs were biallelically expressed. Frequent aberrant hypomethylation was observed at five ubiquitous DMRs, including GRB10 but not ICR2 or ICR1, which regulate the expression of CDKN1C and IGF2, respectively. Whole-exome sequencing performed on four biparental macroscopic PMD specimens did not reveal any pathological genetic abnormalities. Clinical and molecular analyses of babies born from pregnancies with PMD revealed four cases with BWS, each exhibiting different molecular characteristics, and those between BWS and PMD specimens were not always the same.

CONCLUSION

These data clarify the prevalence of biparental PMD and ABM-PMD and strongly implicate hypomethylation of DMRs in the pathogenesis of biparental PMD, particularly placenta-specific DMRs and the ubiquitous GRB10, but not ICR2 or ICR1. Aberrant hypomethylation of DMRs was partial, indicating that it occurs after fertilization. PMD is an imprinting disorder, and it may be a missing link between imprinting disorders and placental disorders incompatible with life, such as complete hydatidiform moles and partial hydatidiform moles.

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.

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.

Lesion Morphology in Multifocal Infantile Hemangiomas

BACKGROUND/OBJECTIVES

Multifocal infantile hemangiomas (MIHs; previously called neonatal hemangiomatosis) can be associated with extracutaneous hemangiomas. We observed different morphologic types of hemangiomas in children with MIHs and sought to find out whether they are related to the clinical course.

METHODS

This was a retrospective study of 103 infants with MIHs and a control group of 261 age-matched patients with solitary focal infantile hemangiomas (IHs) seen at an academic pediatric dermatology department between 2004 and 2014.

RESULTS

Two morphologic subtypes of hemangiomas were identified: miliary focal hemangiomas (MFHs; small, lens shaped) in 58 of 103 MIH patients (56.3%), and classical nonmiliary focal IHs (NMIHs; larger, irregularly shaped) in 17 of 103 patients (16.5%). MIHs featuring both types (mixed type) were observed in 28 of 103 patients (27.2%). MFH lesions were significantly smaller (mean 5.3 mm [range 1-20 mm] vs 22.0 mm [range 2-100 mm]), more numerous (23.4 ± 27.3 [range 5-175] vs 7.4 ± 2.8 [range 5-15] p < 0.001), and occurred up to an older age (6.0 ± 5.8 months [range 0-27 months] vs 3.8 ± 2.6 months [range 0-9 months]) than NMIHs. There was a weakly positive correlation between the number and presence of extracutaneous IHs in children with MFHs. Significantly more children with MIHs were delivered preterm than those with solitary IHs.

CONCLUSIONS

The number of IHs correlates inversely with their size. MFHs follow a clinical course different from that of classical IHs, are associated with prematurity, and may confer greater risk of extracutaneous hemangiomas. Miliary hemangiomas thus appear to present a separate IH subset requiring special attention.

Giant chorioangioma treated in utero via laser of feeding vessels with subsequent development of multifocal infantile hemangiomas

We report a case of a giant placental chorioangioma (15.6 cm diameter) complicated by polyhydramnios and severe fetal heart failure. Fetoscopic laser occlusion of a dominant feeding vessel was performed at 29 weeks' gestation and partial devascularization was achieved. In the 33rd week of the pregnancy, the decision was made to preemptively deliver the fetus due to persistent signs of fetal cardiac failure. After birth, the infant developed multifocal infantile hemangiomas with extracutaneous involvement. We posit that the development of infantile hemangiomas may be linked to the presence of the large chorioangioma. Further study is required to ascertain if fetal treatment of the chorioangioma may have been an exacerbating factor.

An epidemiological study investigating the relationship between chorangioma and infantile hemangioma

OBJECTIVES

This study aimed to verify whether the infantile hemangioma (IH) incidence in children whose placentas showed a chorangioma is higher than in the general population, thus addressing the hypothesized relationship between chorangioma and IH.

METHODS

All chorangioma diagnoses by the 1st Service of Pathology, University of Padova in 2004-2010, based on the analysis of placentas sent by the Department of Gynecological Sciences and Human Reproduction (University of Padova), were identified. Demographic, anamnestic and clinical data were collected from the mothers and newborns; mothers and pediatricians were interviewed by telephone within 1 year after birth to verify if any IH appeared. The incidence rates of IH and other adverse events (IUGR, preterm delivery, cesarean section, stillbirth) were compared with national and regional data, when available, or with estimates from the scientific literature.

RESULTS

Thirty-eight chorangioma diagnoses were found. Of 33 infants born with a placenta affected by chorangioma, 18 infants had IH. The IH incidence recorded in our series (55%) was significantly higher than that recorded in national and regional surveys and in the scientific literature. Similar findings have been observed for the incidence of stillbirth, preterm birth and low birth weight incidence.

CONCLUSIONS

The IH incidence observed in our series appears to be significantly higher than that recorded among the general population, suggesting that an association between placental chorangioma and IH could exist which should be further verified in prospective studies.

Pregnancy with concomitant chorioangioma and placental mesenchymal dysplasia: a rare placental abnormality

Background. Pregnancy with concomitant chorioangioma and placental mesenchymal dysplasia (PMD) coexisting with a normal viable fetus is very rare. The literature was reviewed to explore the incidence and genetic origin of this condition. Case. The case was first identified by prenatal ultrasonography, but the prenatal diagnosis only included chorioangioma. PMD was then confirmed during postnatal evaluation, which included gross and histologic examination of the placenta. The macroscopic and microscopic findings were consistent with concomitant chorioangioma and placental mesenchymal dysplasia during pregnancy. Genetic findings confirmed genetic similarity of the chorioangioma and vesicle-like villi with the fetus. Conclusions. The case represents a rare placental abnormality whose pathogenesis and molecular basis need further research. Detailed histologic and genetic analyses are essential for accurate and differential diagnosis.

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.

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.

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.

Immunohistochemical expression of p57 in placental vascular proliferative disorders of preterm and term placentas

P57 protein is implicated in some human imprinting disorders such as hydatiform mole and Beckwith-Wiedemann syndrome (BWS), both characterized by mesenchymal and vascular placental abnormalities. We investigated p57 immunohistochemical expression in placental vascular proliferative disorders of preterm and term placentas, including chorangiosis (n = 5), chorangiomatosis (n = 2), chorangiomas (n = 7), umbilical cord angioma (n = 1), and placental mesenchymal dysplasia (PMD) (n = 7). P57 was expressed in decidua, cytotrophoblast, intermediate trophoblast and stromal cells of normal terminal, intermediate and stem villi, umbilical cord, chorangiosis, chorangiomatosis, and chorangiomas. In contrast, there was a loss of p57 expression in stromal cells of dysplastic stem villi in all cases of PMD regardless of whether associated with BWS or not. P57 seems to be involved in the pathogenesis of a subset of placental vascular proliferative disorders in preterm and term placentas, such as PMD. The loss of p57 expression in PMD could be of diagnostic value in helping to distinguish this rare placental lesion from its mimickers.

P57kip2 immunohistochemical expression and ultrastructural findings of gestational trophoblastic disease and related disorders

Gestational trophoblastic disease (GTD) is a unique spectrum of diseases ranging from complete hydatidiform mole (CHM), partial hydatidiform mole (PHM), and invasive mole (IM) to choriocarcinoma (CC). Placental site trophoblastic tumor (PSTT) and epithelioid trophoblastic tumor (ETT) have been classified as related disorders. Mesenchymal dysplasia (MD) may be misdiagnosed as PHM; however, it is said to have a quite different histogenesis from PHM. P57kip2 is the protein product of a paternally imprinted or maternal gene that inhibits cyclin-dependent kinases (CDK), thus serving to inhibit cell proliferation and to suppress tumor growth. Its lack of expression in trophoblastic disease plays a role in its abnormal proliferation and differentiation. In this study, P57kip2 immunostaining was absent in the trophoblastic layers of CHM and was positive in the trophoblast layer of nonmolar villi and MD. Ultrastructure of complete molar cystic villi showed tree-like branching of microvillous processes and intracytoplasmic lacunae without capillaries in the stroma, whereas MD contained many newly formed blood vessels and collagen. Also, large lacunae with microvilli and polymorphic nuclei of syncytiotrophoblast cells with well-developed organelles were observed in IM. Lung ETT following CHM and normal deliveries showed two types of large mononuclear cells and binuclear cells with abundant organelles and bundles of intermediate-type filaments in the stroma.

Syndromes and Disorders Associated with Omphalocele (I): Beckwith–Wiedemann Syndrome

Beckwith-Wiedemann syndrome (BWS, OMIM 130650) is characterized by macrosomia, macroglossia, visceromegaly, hemihypertrophy, abdominal wall defects, ear creases/pits, neonatal hypoglycemia, polyhydramnios, placentomegaly, placental mesenchymal dysplasia, cardiac defects, nevus flammeus, hemangiomata, and an increased frequency of embryonal tumors. This article provides an overview of BWS including the genetics, genetic diagnosis, genotype/epigenotype-phenotype correlations, association with assisted reproductive technology, and prenatal diagnosis. Omphalocele is an important sonographic marker for BWS. Prenatal detection of omphalocele, fetal overgrowth, polyhydramnios, increased abdominal circumference, placentomegaly and/or placental mesenchymal dysplasia should alert one to the possibility of BWS and prompt a genetic investigation and counseling for BWS.

Placental mesenchymal dysplasia

CONTEXT

Placental mesenchymal dysplasia is characterized by placentomegaly and may be mistaken for molar pregnancy both clinically and macroscopically because of the presence of "grapelike vesicles." It may be associated with a completely normal fetus, a fetus with growth restriction, or a fetus with features of Beckwith-Wiedemann syndrome.

OBJECTIVE

To review the etiology, molecular pathology, gross and microscopic features, clinical presentation, complications, and differential diagnosis of placental mesenchymal dysplasia.

DATA SOURCES

The PubMed and the Medline databases were systematically searched for articles between 1970 and 2006. The following keywords were used: placental mesenchymal dysplasia, mesenchymal hyperplasia, molar pregnancy, pseudomolar pregnancy, Beckwith-Wiedemann syndrome, and placentomegaly. Relevant references from review articles were also searched.

CONCLUSIONS

Placental mesenchymal dysplasia should be considered in the differential diagnosis when the ultrasonographic findings show a cystic placenta. Close attention should be paid to fetal morphology for early recognition of fetal complications and to prevent unnecessary termination of pregnancy in cases associated with a normal fetus.

Placental mesenchymal dysplasia

Placental mesenchymal dysplasia is a very rare disorder in which the placenta is enlarged and contains cystic villi and dilated vasculature. The authors present a new case report of placental mesenchymal dysplasia with severe fetal growth restriction.

Congenital hepatic mesenchymal hamartoma associated with mesenchymal stem villous hyperplasia of the placenta: case report

A newborn with an unusual association of hepatic mesenchymal hamartoma and mesenchymal stem villous hyperplasia of the placenta is presented. At birth, the large hepatic mass caused severe respiratory distress necessitating early surgical intervention. This report on the association of hepatic mesenchymal hamartoma and mesenchymal stem villous hyperplasia of the placenta strongly suggests a common pathogenetic origin of the 2 lesions.

Placental mesenchymal dysplasia associated with fetal aneuploidy

OBJECTIVES

To describe three cases of placental mesenchymal dysplasia (PMD) associated with abnormal karyotype and review the cases reported in the literature.

METHODS

The cases were retrieved from the files of three different institutions. A search of the English language literature was performed using Medline database.

RESULTS

Placental abnormalities suggestive of molar changes were seen on the prenatal ultrasound scans. Histologically, the cases had large, hydropic stem villi with myxomatous stroma, cistern formation and 'chorangiomatoid' changes. The placental and fetal karyotypes identified were trisomy 13 (47,XX,t(1:13)(q32;q32)+ 13); Klinefelter syndrome (47,XXY) and triploidy (69,XXX). Including these 3 cases, of 66 reported cases, 51 (78%) were female and 14 (22%) male (ratio 3.6:1); the karyotype was normal in 32/36 (89%) and abnormal in 4/36 (11%); Beckwith-Wiedemann syndrome was confirmed or suspected in 15/66 (23%). Excluding termination of pregnancies, intrauterine death occurred in 18/54 (33%) cases.

CONCLUSION

Molar ultrasonographic appearances associated with increased maternal serum alpha-fetoprotein but normal, or slightly elevated, levels of ss human Chorionic Gonadotrophin should raise the clinical suspicion of PMD. The diagnosis of this condition should not be disregarded when an abnormal fetus and/or an abnormal karyotype are demonstrated.

Placental mesenchymal dysplasia initially diagnosed as partial mole

Placental mesenchymal dysplasia is a rare condition of pregnancy that presents as macroscopic features of molar change in the placenta and normal karyotype fetus. These cases are often misdiagnosed as partial mole. We report a new case of mesenchymal dysplasia. A 27-year-old Japanese primigravida delivered an 820 g female baby (46XX karyotype) without congenital anomalies at 27 weeks gestation due to massive bleeding with placenta previa. The placenta had mimicking partial moles, grape-like vesicles and normal villi that diffusely occupied the area on the maternal surface of the placenta. Pathologically, enlarged stem villi contained loose, moderately cellular connective tissue with focal cistern-like formation, and peripherally located vessels. Abnormal trophoblastic proliferation and trophoblastic inclusions were not observed in any of the sections examined. Some villi contained chorioangiomatoid changes. The mother and child were followed up for more than 5 years and showed no sign of trophoblastic disease or Beckwith-Wiedemann syndrome features.

Benign multiple diffuse neonatal hemangiomatosis after a pregnancy complicated by polyhydramnios and a placental chorioangioma

A male newborn with multiple cutaneous hemangiomatosis is described. Pregnancy was complicated by polyhydramnios and a large placental chorioangioma. After an initial outburst of the hemangiomas in the first two weeks of life, spontaneous and almost complete regression occurred before the age of 3 months. The relationship between hemangiomas and placental chorioangioma is briefly discussed.

Suspected involvement of the X chromosome in placental mesenchymal dysplasia

So far, 46 cases of placental mesenchymal dysplasia have been reported worldwide. We encountered 15 cases of placental mesenchymal dysplasia (PMD) including 7 cases delivered in our hospital. The incidence of PMD in our hospital was therefore, 7/30,758 (0.02%). The PMD had a peculiar appearance. In the gross findings, large placenta with intestine-like dilatation of the vessels on the fetal side was reported. Microscopically, cistern-like dilatation of the stem villi, fetal artery thrombosis, and villous hemorrhage were reported. However, we believe most of these findings are secondary rather than the primary of mesenchymal dysplasia. Therefore, we investigated 15 other cases of mesenchymal dysplasia, and found including vascular abnormality of the stem, intermediate and terminal villi in all case of PMD. The abnormality was observed in the vessels of the periphery of the stem villi and their vessel walls were thin and appeared weak. The intermediate villous vessels were unusual, tangled. The terminal villous abnormalities showed chorangiosis and stromal hyperplasia. These findings are mesenchymal dysplasia origin. Moreover, PMD showed female-predominant. 14/15 was female among our cases, We discuss the relationship between mesenchymal dysplasia and the X chromosome in this paper.

Mesenchymal dysplasia of the placenta

A severe case of placental mesenchymal dysplasia occurred in association with intrauterine fetal death (IUFD). The gravida-1, para-1 mother was a 26-year-old Japanese. The first pregnancy was unremarkable and a healthy female infant was delivered. The present pregnancy had been uneventful until 34 weeks of gestation when IUFD was detected. The 1516-g (mean +/- SD, 2050 +/- 387 g) stillborn infant had no external abnormalities and the karyotype was 46,XX. The placenta was markedly enlarged (1050 g; mean +/- SD, 452 +/- 202 g), and approximately 80% was occupied by extraordinary enlarged villous structures with a myxoid appearance. Histologically, the dysplastic villi had myxoid stroma and a decreased number of, occasionally obliterated, fetal vessels. There was no abnormal trophoblastic proliferation. Large-sized fetal vessels in the chorionic plate frequently contained organized thrombi. This is the first case of placental mesenchymal dysplasia, which possibly lead to the IUFD.