Human triploidy: association with partial hydatidiform moles and nonmolar conceptuses

Placental Pathology Findings in Unexplained Pregnancy Losses

There are approximately 5 million pregnancies per year in the USA, with 1 million ending in miscarriage (a loss occurring prior to 20 weeks of gestation) and over 20,000 ending in stillbirth at or beyond 20 weeks of gestation. As many as 50% of these losses are unexplained. Our objective was to evaluate the effect of expanding the placental pathology diagnostic categories to include the explicit categories of (1) dysmorphic chorionic villi and (2) small placenta in examining previously unexplained losses. Using a clinical database of 1256 previously unexplained losses at 6-43 weeks of gestation, the most prevalent abnormality associated with each loss was determined through examination of its placental pathology slides. Of 1256 cases analyzed from 922 patients, there were 878 (69.9%) miscarriages and 378 (30.1%) antepartum stillbirths. We determined the pathologic diagnoses for 1150/1256 (91.6%) of the entire series, 777/878 (88.5%) of the miscarriages (< 20 weeks' gestation), and 373/378 (98.7%) of the stillbirths (≥ 20 weeks' gestation). The most common pathologic feature observed in unexplained miscarriages was dysmorphic chorionic villi (757 cases; 86.2%), a marker associated with genetic abnormalities. The most common pathologic feature observed in unexplained stillbirths was a small placenta (128 cases; 33.9%). Our classification system reinforced the utility of placental examination for elucidating potential mechanisms behind pregnancy loss. The improved rate of diagnosis appeared to be the result of filling a gap in previous pregnancy loss classification systems via inclusion of the categories of dysmorphic chorionic villi and small placenta.

Gestational Trophoblastic Disease: Contemporary Diagnostic Approach

Pathologic diagnosis of gestational trophoblastic disease (GTD)-hydatidiform moles and gestational trophoblastic neoplasms-underwent a major shift in the past decade from morphology-based recognition to precise molecular genetic classification of entities, which also allows for prognostic stratification of molar gestations. This article highlights these recent advances and their integration into the routine pathology practice. The traditional gross and histomorphologic features of each entity are also reviewed with special focus on differential diagnoses and their clinical implications.

Derivation of human triploid trophoblast stem cells

PURPOSE

Human trophoblast stem cells (hTSCs) are counterparts of the precursor cells of the placenta and are valuable cell models for the study of placental development and the pathogenesis of placental diseases. The aim of this work was to establish a triploid human TSC (hTSC^3PN) derived from the tripronuclear embryos, which are clinically discarded but readily available, for potential applications in basic placental research and disease modeling.

METHODS

Eighteen tripronuclear human zygotes from IVF were collected and cultured for 5-6 days. Five high-quality blastocysts were harvested and were individually cultured in hTSC medium. Finally, two hTSC lines were established after 10 days and could be passaged stably.

RESULTS

The karyotyping analysis showed that hTSC^3PN contained three sets of chromosomes. And the hTSC^3PN exhibited typical features of hTSCs, with the ability to differentiate into two trophoblast lineages: extravillous cytotrophoblasts (EVTs) and syncytiotrophoblasts (STs). In addition, the hTSC^3PN can mimic some vital features of trophoblast, including hormone secretion and invasion. Further studies showed that the proliferation and differentiation of hTSC^3PN were reduced compared with normal hTSCs, which may be related to the disturbed metabolic signaling in hTSC^3PN.

CONCLUSIONS

We established the triploid hTSC lines derived from tripronuclear embryos, which provides a potentially useful research model in vitro to study human placental biology and diseases.

Trophoblast inclusions and adverse birth outcomes

OBJECTIVE

Trophoblast inclusions-cross sections of abnormal trophoblast bilayer infoldings-have previously been associated with aneuploidy, placenta accreta, and prematurity. This study was conducted to establish the relationship between trophoblast inclusions and a range of placental, pregnancy, and birth outcomes in a patient population with high smoking and alcohol exposure. Specifically, we sought to evaluate the association between the presence of trophoblast inclusions and 1) three primary birth outcomes: full-term birth, preterm birth, and stillbirth; 2) gestational age at delivery; and 3) specific placental pathologies.

METHODS

Two slides containing chorionic villi were evaluated from 589 placentas that were collected from Stellenbosch University in Cape Town, South Africa as part of the prospective, multicenter cohort Safe Passage Study of the Prenatal Alcohol and SIDS and Stillbirth Network. The subsample included 307 full-term live births, 212 preterm live births, and 70 stillbirths.

RESULTS

We found that the odds of identifying at least one trophoblast inclusion across two slides of chorionic villi was significantly higher for placentas from preterm compared to term liveborn deliveries (OR = 1.74; 95% CI: 1.22, 2.49, p = 0.002), with an even greater odds ratio for placentas from stillborn compared to term liveborn deliveries (OR = 4.95; 95% CI: 2.78, 8.80, p < 0.001). Gestational age at delivery was inversely associated with trophoblast inclusion frequency. Trophoblast inclusions were significantly associated with small for gestational age birthweight, induction of labor, villous edema, placental infarction, and inflammation of the chorionic plate.

CONCLUSIONS

The novel associations that we report warrant further investigation in order to understand the complex network of biological mechanisms through which the factors that lead to trophoblast inclusions may influence or reflect the trajectory and health of a pregnancy. Ultimately, this line of research may provide critical insights that could inform both clinical and research applications.

Genotyping diagnosis of gestational trophoblastic disease: frontiers in precision medicine

Investigations in recent decades have exploited tissue DNA genotyping as a powerful ancillary tool for the precision diagnosis and subclassification of gestational trophoblastic disease. As lesions of gestational origin, the inherited paternal genome, with or without copy number alterations, is the fundamental molecular basis for the diagnostic applications of DNA genotyping. Genotyping is now considered the gold standard in the confirmation and subtyping of sporadic hydatidiform moles. Although a precise diagnosis of partial mole requires DNA genotyping, prognostic stratification according to distinct genetic zygosity in complete moles has recently gained significant clinical relevance for patient care. Beyond hydatidiform moles, DNA genotyping has fundamental applications in the diagnosis or prognostic assessment of gestational trophoblastic tumors, in particular gestational choriocarcinoma. DNA genotyping provides a decisive tool in the separation of gestational trophoblastic neoplasia from non-gestational counterparts/mimics of either germ cell or somatic origin. The FIGO/WHO prognostic scoring scheme requires ascertaining the precise index gestational event and the time interval between the tumor and index gestation, where DNA genotyping can provide highly relevant information. With rapid acquisition of molecular diagnostic capabilities in the clinical practice, DNA genotyping has become closely integrated into the routine diagnostic workup of various forms of gestational trophoblastic disease.

Refined diagnosis of hydatidiform moles with p57 immunohistochemistry and molecular genotyping: updated analysis of a prospective series of 2217 cases

Immunohistochemical analysis of p57 expression and molecular genotyping accurately subclassify molar specimens into complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM) and distinguish these from nonmolar specimens. Characteristics of a prospective series of potentially molar specimens analyzed in a large gynecologic pathology practice are summarized. Of 2217 cases (2160 uterine, 57 ectopic), 2080 (94%) were successfully classified: 571 CHMs (570 uterine, 1 ectopic), 498 PHMs (497 uterine, 1 ectopic), 900 nonmolar (including 147 trisomies, 19 digynic triploids, and 4 donor egg conceptions), and 56 androgenetic/biparental mosaics; 137 were complex or unsatisfactory and not definitively classified. CHMs dominated in patients aged < 21 and >45 years and were the only kind of molar conception found in the latter group. Of 564 successfully immunostained CHMs, 563 (99.8%) were p57-negative (1 p57-positive [retained maternal chromosome 11] androgenetic by genotyping). Of 153 genotyped CHMs, 148 (96.7%) were androgenetic (85% monospermic) and 5 were biparental, the latter likely familial biparental hydatidiform moles. Of 486 successfully immunostained PHMs, 481 (99%) were p57-positive (3 p57-negative [loss of maternal chromosome 11], 2 unknown mechanism). Of 497 genotyped PHMs, 484 (97%) were diandric triploid (99% dispermic) and 13 were triandric tetraploid (all at least dispermic). Of 56 androgenetic/biparental mosaics, 37 had a p57-negative complete molar component (16 confirmed as androgenetic by genotyping). p57 expression is highly correlated with genotyping, serving as a reliable marker for CHMs, and identifies molar components and androgenetic cell lines in mosaic conceptions. Correlation of morphology, p57 expression, genotyping data, and history are required to recognize familial biparental hydatidiform moles and donor egg conceptions, as the former can be misclassified as nonmolar and the latter can be misclassified as dispermic CHM on the basis of isolated genotyping results.

Prenatal sonographic features can accurately determine parental origin in triploid pregnancies

Objective

To describe the prenatal sonographic features and maternal biochemical markers in triploid pregnancies and to assess whether prenatal phenotype can determine genetic origin.

Methods

We performed a retrospective multicenter cohort study that included all triploid pregnancies diagnosed between 2000 and 2018 in two Fetal Medicine Units in Amsterdam. Fetal growth, presence of structural anomalies, extra‐fetal anomalies, and maternal biochemical markers were retrieved. Asymmetrical intrauterine growth restriction was diagnosed when the head‐to‐abdominal circumference (HC/AC) ratio was >95th centile. Parental origin was analyzed via molecular genotyping in 46 cases (38.3%).

Results

One hundred and twenty triploid pregnancies were identified, of which 86 cases (71.6%) were detected before 18 weeks of gestation. Triploidy of maternal origin was found in 32 cases (69.6%) and was associated with asymmetrical growth restriction, a thin placenta, and low pregnancy‐associated plasma protein A and free beta‐human chorionic gonadotrophin (β‐hCG) levels. Triploidy of paternal origin was found in 14 cases (30.4%) and was associated with an increased nuchal translucency, placental molar changes, and a high free β‐hCG. Prospective prediction of the parental origin of the triploidy was made in 30 of the 46 cases based on phenotypical ultrasound presentation, and it was correct in all cases.

Conclusion

Asymmetrical growth restriction with severe HC/AC discrepancy is pathognomonic of maternal triploidy. Placental molar changes indicate a paternal triploidy. Moreover, triploidy can present with an abnormal first trimester combined test, with serum levels on the extreme end. When available results of maternal serum markers can support the diagnosis of parental origin of the triploidy, an accurate assessment of the parental origin based on prenatal sonographic features is possible, making DNA analysis redundant.

Diploid/triploid mixoploidy: A consequence of asymmetric zygotic segregation of parental genomes

Triploidy is the presence of an extra haploid set of chromosomes and can exist in complete or mosaic form. The extra haploid set of chromosomes in triploid cells can be of maternal or paternal origin. Diploid/triploid mixoploidy is a unique form of triploid mosaicism that requires the aberrant segregation of entire parental genomes into distinct blastomere lineages (heterogoneic cell division) at the earliest zygotic divisions. Here we report on eight cases of diploid/triploid mixoploidy from our institution and conduct a comprehensive review of the literature. The parental origin of the extra set of chromosomes was determined in two cases; and, based on phenotypic evidence we propose the parental origin in the other cases. One case with complex mixoploidy appears to have a digynic origin in addition to the involvement of two different sperm. Of our eight cases, only one resulted in the birth of a live healthy child. The other pregnancies ended in miscarriage, elective termination of pregnancy, intrauterine fetal demise or neonatal death. A review of the literature and the results of our cases show that a preponderance of recognized cases of diploid/triploid mixoploidy has a digynic origin.

Is There a Correlation Between Histology and Karyotype in Early Spontaneous Abortion?

The value of histologic evaluation of placental tissue in spontaneous abortions remains undefined. We analyzed 90 placentas from early spontaneous abortions to ascertain if morphologic features were predictive of karyotype. Normal karyotypes were observed in 40 cases, and abnormal karyotypes were found in 50. There were 25 trisomies, 6 triploidies, 2 tetraploidies, one 45, × 0, and 16 other abnormalities, such as mosaic and chimera. All 6 triploid placentas were partial moles. The pres ence of intravillous cistern formation and focal trophoblastic hyperplasia was seen more frequently in cases with abnormal karyotypes. The triploid cases, however, contributed the majority of cases with these villous changes. Hydropic abortion was observed approximately equally in both chromosomally normal and abnormal cases, and its incidence was high in cases of trisomy 16 and tetraploid placenta. Mild edema and regressive changes, such as stromal fibrosis, hypovascular stroma, and attenuated trophoblastic layers, were often found and none showed any specific chromosomal abnormalities. These results indicate that histology can provide only a suggestion as to the likelihood of triploidy and that histologic examination of spontaneous abortions is not useful as a method for predicting chromosomal abnor mality. Int J Surg Pathol 2(4):295-300, 1995

Triploidy: Variation of Phenotype

OBJECTIVES

Triploidy (69, XXX; 69, XXY; 69, XYY) accounts for 1% of conceptions, but the affected fetus often does not survive past the first trimester. Fetal development in triploidy is rare. A consecutive series was used to describe the fetal and placental phenotypes and compare them with previous publications.

METHODS

Fifty-four triploid fetuses were identified in the Active Malformations Surveillance Program between 1972 and 2012 at Brigham and Women's Hospital in Boston. The phenotype was described from prenatal imaging and autopsy findings.

RESULTS

The diagnosis was confirmed by chromosome analysis in 53 of the 54 fetuses. Twenty-seven (50%) of the affected fetuses were identified during pregnancy. The abnormalities identified by prenatal ultrasound included renal malformations, heart defects, hydrocephalus, holoprosencephaly, and myelomeningocele. At autopsy, syndactyly, usually between fingers 3 and 4, was identified in 37 (69%) of the fetuses. Thirteen (24%) of the infants had the histologic features of a partial hydatidiform mole in the placenta.

CONCLUSIONS

The presence of major malformations and growth restriction during pregnancy makes triploidy a potential diagnosis. There are no obligate clinical features in triploidy. Syndactyly, especially 3-4 syndactyly of the hands, is a distinctive feature. Cystic changes in the placenta can be seen by ultrasound during pregnancy. There was no difference in the phenotype between triploid infants associated with partial moles and those with nonmolar placentas.

Triploidy--Observations in 154 Diandric Cases

Hydatidiform moles (HMs) are abnormal human pregnancies with vesicular chorionic villi, imposing two clinical challenges; miscarriage and a risk of gestational trophoblastic neoplasia (GTN). The parental type of most HMs are either diandric diploid (PP) or diandric triploid (PPM). We consecutively collected 154 triploid or near-triploid samples from conceptuses with vesicular chorionic villi. We used analysis of DNA markers and/or methylation sensitive-MLPA and collected data from registries and patients records. We performed whole genome SNP analysis of one case of twinning (PP+PM).In all 154 triploids or near-triploids we found two different paternal contributions to the genome (P1P2M). The ratios between the sex chromosomal constitutions XXX, XXY, and XYY were 5.7: 6.9: 1.0. No cases of GTN were observed. Our results corroborate that all triploid human conceptuses with vesicular chorionic villi have the parental type P1P2M. The sex chromosomal ratios suggest approximately equal frequencies of meiosis I and meiosis II errors with selection against the XYY conceptuses or a combination of dispermy, non-disjunction in meiosis I and meiosis II and selection against XYY conceptuses. Although single cases of GTN after a triploid HM have been reported, the results of this study combined with data from previous prospective studies estimate the risk of GTN after a triploid mole to 0% (95% CI: 0–1,4%).

Triploid pregnancies: genetic and clinical features of 158 cases

OBJECTIVE

The purpose of this study was to analyze the correlation between the genetic constitution and the phenotype in triploid pregnancies.

STUDY DESIGN

One hundred fifty-eight triploid pregnancies were identified in hospitals in Western Denmark from April 1986 to April 2010. Clinical data and karyotypes were collected retrospectively, and archived samples were retrieved. The parental origin of the genome, either double paternal contribution (PPM) or double maternal contribution (MMP) was determined by an analysis of methylation levels at imprinted sites.

RESULTS

There were significantly more PPM than MMP cases (P < .01). In MMP cases, the possible karyotypes had similar frequencies, whereas, in PPM cases, 43% had the karyotype 69,XXX, 51% had the karyotype 69,XXY, and 6% had the karyotype 69,XYY. Molar phenotype was seen only in PPM cases. However, PPM cases with a nonmolar phenotype were also seen. For both parental genotypes, various fetal phenotypes were seen at autopsy. Levels of human chorionic gonadotropin in maternal serum were low in MMP cases and varying in PPM cases, some being as low as in the MMP cases.

CONCLUSION

In a triploid pregnancy, suspicion of hydatidiform mole at ultrasound scanning, by macroscopic inspection of the evacuated tissue, at histology, or because of a high human chorionic gonadotropin in maternal serum level each predict the parental type PPM with a very high specificity. In contrast, the sensitivity of these observations was <100%.

[Partial invasive and metastatic hydatidiform mole: report of a case]

Depuis plusieurs années, la môle hydatiforme partielle(MHP) a été considérée comme une entité bénigne qui ne nécessite pas une surveillance stricte comme celle de la môle complète(MC), mais l'apparition de quelques cas sporadiques de transformation de la môle partielle en maladie trophoblastique persistante que ça soit une môle invasive ou choriocarcinome ou voire même une tumeur du site d'implantation placentaire; a remis en question cette stratégie. A travers une observation d'une môle partielle invasive métastatique, et à travers une revue de la littérature, on a essayé d'appuyer cette conduite qui considère la môle partielle comme une pathologie potentiellement grave nécessitant une prise en charge adéquate et une surveillance assez rigoureuse.

Trophoblast inclusions are significantly increased in the placentas of children in families at risk for autism

BACKGROUND

Gestation is a critical window for neurodevelopmental vulnerability. This study examined whether the presence of trophoblast inclusions (TIs) in the placenta could serve as a predictor for children at elevated risk for autism spectrum disorder (ASD).

METHODS

Placentas were obtained from 117 births in the MARBLES (Markers of Autism Risk in Babies-Learning Early Signs) cohort of families who have one or more previous biological children with ASD, placing their newborn at elevated risk for neurodevelopmental compromise. Control samples were obtained from 100 uncomplicated term pregnancies of multiparous women with one or more typically developing biological children. Frequency of TIs was compared across the two groups.

RESULTS

Placentas from at-risk pregnancies had an eightfold increased odds of having two or more TIs compared with control samples (odds ratio: 8.0, 95% confidence interval: 3.6-18.0). The presence of≥2 TIs yielded a sensitivity of 41% and a specificity of 92% for predicting ASD risk status, whereas≥4 TIs yielded a sensitivity of 19%, a specificity of 99.9%, and a positive likelihood ratio of 242 and conservatively predicted an infant with a 74% probability of being at risk for ASD.

CONCLUSIONS

Our findings suggest that the placentas from women whose fetuses are at elevated risk for autism are markedly different from control placentas. These differences are manifested histologically as TIs. Their identification has the possibility of identifying newborns at risk for ASD who might benefit from targeted early interventions aimed at preventing or ameliorating behavioral symptoms and optimizing developmental outcomes.

Establishment of a new diagnostic method for hydropic villi by using TSSC3 antibody

A total of 297 samples of hydropic villi were classified according to DNA polymorphisms as androgenetic moles, dispermic triploids, or biparental diploids. A subset of 267 appropriate samples was included in the study. Most of the macroscopically diagnosed complete mole cases were genetically androgenetic in origin. The partial mole cases consisted of 30 androgenetic moles and 12 dispermic triploids. For the 59 cases macroscopically categorized as hydropic abortion, the genetic analysis revealed 38 androgenetic moles, seven dispermic triploids and 14 biparental diploids. These results showed that a new diagnostic method was required for the management of patients with hydropic villi. We identified the TSSC imprint gene of which expression was shown in normal and partial mole villi but was silenced in complete mole villi. Immunohistochemistry using the TSSC3 antibody demonstrated its efficacy as the differential diagnostic method. TSSC3 play an important role in the differentiation from trophoblast stem cells to progenitors and/or labyrinth trophoblast through the TSSC3/PI3K/Akt/Mash2 signaling pathway.

Placental trophoblast inclusions in autism spectrum disorder

BACKGROUND

Microscopic examination of placental tissue may provide a route to assessing risk and understanding underlying biology of autism.

METHODS

Occurrence of a distinctive microscopic placental morphological abnormality, the trophoblast inclusion, was assessed using archived placental tissue. The rate of occurrence of trophoblast inclusion-positive slides observed for 13 individuals with autism spectrum disorder (ASD) was compared to the rate in an anonymous consecutive birth cohort.

RESULTS

The occurrence of inclusion positive slides was significantly greater in the ASD group compared to the control group (6/27 slides, 22.2% vs. 12/154, 7.8%; Fisher Exact Test, two-tailed p = .033; relative risk 2.85). The proportion of positive cases was also greater in the ASD group (5/13 cases, 38.5% vs. 8/61, 13.1%; Fisher Exact, two-tailed p = .044; relative risk 2.93). Behavioral severity scores did not differ across groups of inclusion positive (N = 4) and negative (N = 8) ASD individuals.

CONCLUSIONS

Although probably not functionally detrimental or causative, the greater occurrence of placental trophoblast inclusions observed in ASD individuals may reflect altered early developmental processes. Further research is required to replicate the basic finding, to understand the basis for the trophoblastic abnormality, and to determine the utility of the measure in early detection of ASD.

Choriocarcinoma and gestational trophoblastic disease

Gestational trophoblastic disease (GTD) encompasses a unique group of uncommon but interrelated conditions derived from placental trophoblasts. For the purposes of discussion GTD is the appropriate collective name for hydatidiform mole, whereas the term gestational trophoblastic neoplasia (GTN) is reserved for cases with persistent human chorionic gonadotropin (hCG) titer elevation after evacuation of hydatidiform mole, metastatic disease, or choriocarcinoma. Although the pathology and clinical behavior of CM and PM are different, the initial management of both conditions is surgical evacuation by suction curettage, determination of the baseline, and follow-up with (hCG) titers. There are guidelines for risk-factor scoring and a staging system that classifies untreated patients into distinct prognostic categories so that treatment outcomes can be objectively compared. The rates of GTN and choriocarcinoma are decreasing and survival has dramatically improved.

The Placenta Revisited: Radiologic–Pathologic Correlation

The placenta is the central support organ for the developing fetus. Recognition of placental variants and insignificant findings is important so as not to suggest an abnormality when one is not present. However, the degree of abnormality, as well as the clinical implications of the findings, must be understood to help guide management of the pregnancy. This article reviews the normal sonographic appearance of the placenta and some anatomic variants, in addition to illustrating various common pathological conditions of the placenta and correlating with gross pathologic and histologic specimens.

Phenotype of triploid embryos

The phenotypes of triploid fetuses and placentae are now well established and known to correlate with parental origin of the extra haploid set of chromosomes. In fetuses, it is not clear whether there is a direct parent of origin effect on the fetus itself or if the phenotypes are the result of growth differences influenced by abnormalities in growth and function of the placenta. Examining the phenotype of triploid embryos at an earlier stage in gestation, when the placenta effects may be less pronounced, could help clarify this question. A phenotype characteristic of triploidy in the embryonic period has been described; however, parental origin was not determined in these embryonic cases. In the present study, a population of triploid embryos is assessed to determine if there is a correlation between parental origin and phenotype. Parental origin was determined in 27 first trimester miscarriages. Digyny accounted for 19 cases and diandry for eight cases. Assessment of embryonic phenotype with parental origin showed no correlation between the phenotype of the embryo and parental origin of the extra haploid set. While there may be subtle effects of imprinting on embryonic development, they are not as obvious as they are in the mouse, consistent with the general trend of fewer imprinted genes in human beings compared with the mouse.

Interobserver and Intraobserver Variability in the Diagnosis of Hydatidiform Mole

Surgical pathologists often encounter hydropic villi in products of conception at the first trimester and must determine whether the villi represent complete hydatidiform mole (CM), partial hydatidiform mole (PM), or hydropic abortion (HA). The distinction between these is important for determining the appropriate treatment of patients. This study assessed interobserver and intraobserver variability in the histologic diagnosis of hydatidiform mole among 5 placental pathologists. To evaluate interobserver variability, one representative slide from each of 50 mixed cases of PM, CM, and HA of the first trimester were circulated among 5 placental pathologists. All pathologists used the same histologic criteria by Szulman and Surti. For the second round, the same cases were submitted with DNA ploidy data. For the third round, the slides were recoded and distributed to assess intraobserver agreement. Kappa (kappa) value was calculated for the interobserver agreement in the first and second rounds. There was agreement among 4 or 5 pathologists for only 30 of 50 cases in the first round. There were problems in differentiating between PM and HA in most of the remaining 20 cases. The kappa values varied from poor (kappa = -0.104) to excellent (kappa = 0.761) in the first round. In the second round, there was agreement in 39 of 50 cases and the level of agreement remarkably increased, ranging from fair to good (kappa = 0.552) to excellent (kappa = 0.851). The number of discrepant cases, PM versus HA, was reduced to 4. In 7 cases, there were difficulties in distinguishing CM from HA. The intraobserver agreement ranged from 50% to 90%. Poor interobserver agreement was demonstrated when histology alone was used for diagnosis. Discordance was most frequently seen in PM versus HA and resulted from difficulty in evaluating trophoblastic hyperplasia. Polar trophoblastic growth seen in HA could also be observed in PM. The addition of ploidy data resulted in a significant improvement in concordance. Ploidy study is useful in equivocal cases. Significant interobserver and intraobserver variability was observed even among placental pathologists. New histologic criteria adaptable to differentiation of early lesions are needed.

Complete hydatidiform mole in Hawaii: An epidemiological study

An analysis of hydatidiform moles occurring in Hawaii over a 14-year period (1968-1981) was undertaken. The pathology of all 278 reported molar pregnancies was reviewed and showed 69.4% to be complete, 24.5% to be partial, and 6.1% to be nonmolar. A case-control epidemiological investigation of the complete moles showed maternal age and race to be important, moles being significantly more prevalent in women under 20 and over 40 yr of age and also in women of Japanese, Filipino, and other Oriental ancestry. However no difference was seen in the prevalence of moles between Oriental women born in the Orient and those born and raised in Hawaii. No significant difference was found in paternal age, paternal race, socioeconomic status, or reproductive history, suggesting that these factors do not play an important role in the etiology of complete hydatidiform mole. Incidence rates for complete moles were calculated taking age and race into consideration and ranged from a high of 1 in 150 to a low of 1 in 2,000 naturally terminating pregnancies.

Vasculogenesis in complete and partial hydatidiform mole pregnancies studied with CD34 immunohistochemistry

BACKGROUND

Defective chorionic villous vascularization is present in pregnancies complicated by absent or abnormal embryonic development. The aim of this study was to investigate the embryonic and/or maternal genomic influence on vasculogenesis in diploid complete hydatidiform mole (CHM) and in triploid partial hydatidiform mole (PHM) in comparison with normal development.

METHODS

Mean villous stromal area and functional vascular area, vessels with a lumen and haemangiogenetic cords, peripherally or centrally located were measured and counted in chorionic villi of 12 CHM, 12 normal pregnancies (termination of pregnancy, TOP) and 15 PHM of which nine were without an embryo (PHM-E) and six were with an embryo (PHM + E), using quantitative CD34 immunohistochemistry.

RESULTS

TOP showed significantly more vessels per chorionic villus, centrally and peripherally located (median, range), than CHM, PHM-E and PHM + E (4.0, 0-9 versus 0.0, 0-11, 0.0, 0-18 and 1.0, 0-21). CHM showed significantly more centrally located cords than PHM-E, PHM + E and TOP (1.5, 0-22 versus 1.0, 0-15, 0.5, 0-8 and 1.0, 0-2).

CONCLUSIONS

Initiation of chorionic villous vasculogenesis is independent of the maternal genome (CHM). The development of an embryo, however, is obligatory for the modulation of normal vascularization resulting in a well developed vasculosyncytial membrane.

Sonographic, pathologic and karyotypic findings in a rare case of placenta fenestrata

Abnormalities of placental shape are occasionally seen on ultrasound. They have not been reported to be associated with abnormalities in fetal anatomy and karyotype. Here, we report on a rare case of placenta fenestrata with triploid karyotype. A 15-year-old patient presented at 21 weeks and 3 days gestation for ultrasound evaluation following an abnormal triple screen and abnormal ultrasound. Multiple fetal abnormalities were noted as well as several cystic areas with pulsatile flow on Doppler ultrasound in the placenta. After termination of the pregnancy, a rare abnormality in the placental shape, placenta fenestrata, was noted. The fetal karyotyping showed a triploid karyotype. This is the first reported case of placenta fenestrata diagnosed on ultrasound. In addition, this is also the first reported case of karyotype abnormality associated with abnormality of placental shape.

Genetics and molecular markers in gestational trophoblastic disease with special reference to their clinical application

Gestational trophoblastic disease (GTD) encompasses a diverse group of lesions with specific cytogenetic and molecular pathogenesis. Although cytogenetic studies have been extensively reported, the molecular pathogenesis is poorly understood. We will summarize some of the recent molecular observations and correlate them with the pathology of GTD. Complete mole is androgenetic in origin. Thus, if a monoallelic contribution can be shown in complete mole, this would render the gene susceptible to functional inactivation by 'one-hit' kinetics. Alternatively, uniparental transmission of genes that are subject to parental imprinting in humans would impair their regulation. Loss of NECC1 expression, biallelic deletions at the critical (7p12-7q11.23) region and enhanced H19 expression in choriocarcinoma would reflect the genetic features exhibited by the putative forerunner, complete mole. In addition to the unique genetic features shown in GTD, alterations in gene expression profiles accompanied by malignant conversion of trophoblasts would facilitate the development of choriocarcinogenesis from complete mole. With recent advances in molecular techniques, further work is still necessary to provide a better understanding and useful markers for persistent trophoblastic disease. These may provide useful prognostic indications that may guide the different diagnosis of GTD.

Refining the diagnosis of hydatidiform mole: image ploidy analysis and p57KIP2 immunohistochemistry

AIM

To determine whether image analysis of ploidy status and immunohistochemical analysis of p57KIP2 (a paternally imprinted, maternally expressed gene) can be used to refine the diagnosis of molar pregnancy.

METHODS AND RESULTS

The original histological diagnosis in 40 randomly selected cases of hydatidiform mole was reviewed and confirmed in 38 cases (22 complete moles, 16 partial moles). These cases were anonymized and submitted for further analysis. Tissue from each case was submitted for flow cytometric assessment of DNA ploidy using a FACSort flow cytometer and for automated image cytometric assessment using a novel digital imaging system. Tissue sections from each case were immunostained with a monoclonal mouse antibody to p57KIP2. Correlations between the histopathological diagnosis, image cytometry, flow cytometry and p57KIP2 immunohistochemistry were determined using kappa statistics. The concordance between histological diagnosis and p57KIP2 was very good (kappa = 0.89). Twenty of the 22 (90.9%) complete moles showed no immunoreactivity for p57KIP2. The remaining two cases showed nuclear immunoreactivity in villous cytotrophoblast. In one of these, the pattern of staining resembled that of a partial mole. In the other, the staining pattern supported the diagnosis of a twin molar/non-molar pregnancy. All 16 partial moles were p57KIP2 immunoreactive. On flow cytometry, all 22 complete moles were diploid and 12/16 partial moles were triploid (the remaining four cases originally diagnosed as partial moles were found to be diploid). On image cytometry, one case originally diagnosed as complete mole was found to contain a triploid population. Thus, by using a combination of image cytometry and p57KIP2 status we were able to refine the diagnosis of molar pregnancy in five (13%) of the cases studied.

CONCLUSIONS

Automated image cytometry is a readily performed investigation which is comparable to, but more sensitive than, flow cytometry. Complementary use of ploidy analysis and p57KIP2 status can now help to distinguish a diploid hydropic miscarriage (p57KIP2-positive), diploid complete mole (p57KIP2-negative) and triploid partial mole (p57KIP2-positive).

Second trimester maternal serum analytes in triploid pregnancies: correlation with phenotype and sex chromosome complement

Second trimester maternal serum alpha-fetoprotein (MS-AFP), human chorionic gonadotrophin (hCG), unconjugated estiol (uE3), and inhibin-A (INH-A) levels were evaluated in pregnancies complicated by triploidy. In addition to seven new triploid pregnancies, the results for 67 published cases were reviewed. All cases appear to fall into two major groups. First, those identifiable as screen-positive for both Down syndrome and an open neural tube defect (ONTD) with elevated MS-AFP, grossly elevated hCG, low/normal uE3, and probably elevated INH-A. Pregnancies in the second group are identifiable as screen-positive for trisomy 18 with low/normal MS-AFP, and very low hCG, uE3 and INH-A. Triploid pregnancies with high maternal serum hCG nearly always show a placenta with partial mole (25/27 or 93%), a high frequency of ONTDs or ventral wall defects (VWDs) (8/28 or 29%) and have either an XXX or XXY karyotype (observed ratio 6:10, respectively). Low hCG is infrequently associated with a molar placenta (1/11 or 9%), does not appear to be associated with ONTDs or VWDs (0/29 or 0%), and shows an excess of XXX over XXY karyotypes (observed ratio 17:2). There were 16 cases with either a molar placenta, an ONTD or a VWD that received the MS-AFP and hCG tests. All 16 were screen-positive for an ONTD (MS-AFP> or =2 multiples of the median). In addition, all 31 cases that received MS-AFP, hCG, uE3 (and where available INH-A) were screen-positive for either Down syndrome or trisomy 18. The findings are discussed in the context of expected differences between digynic and diandric triploidy. It is suggested that the sex chromosome complement in triploidy is an important factor in determining risk for partial mole development and in utero survival.

Parental and meiotic origin of triploidy in the embryonic and fetal periods

Triploidy is a common finding both in early spontaneous abortions and in the fetal period. Previous studies suggested that the majority of triploidy was the result of diandry, specifically dispermy. Molecular determination of parental origin in fetal triploids has shown that digyny accounts for the majority of triploids in the fetal period. The aim of this study was to determine the meiotic level at which the error leading to digynic triploidy occurs and to extend the molecular analysis of parental origin of triploidy into the embryonic period. Maternal age of digynic triploids was compared with that of the diandric cases. Using polymorphic pericentromeric markers, we have shown that the majority of digynic triploidy is the result of errors in the second meiotic division. Digyny accounted for the majority of triploids, even in the nonfetal cases. Diandry predominated in a subset of the non-fetal cases in which embryos were not present and in which the placental findings of partial hydatidiform mole (PHM) were encountered. Maternal age differed between the digynic and diandric groups only for the non-fetal cases; this was attributed to differences in ascertainment.

Partial mole, triploidy and proteinuric hypertension: two case reports

We present two cases of proteinuric hypertension in the early second trimester of pregnancy, associated with partial mole and triploidy karyotyping. This demonstrates the complementary nature of ultrasound in the diagnosis and management of this rare association.

Pronuclear location before the first cell division determines ploidy of polyspermic pig embryos

Polyspermy occurs frequently in the fertilization of mammalian eggs, but little is known about whether polyspermic eggs have developmental ability in vitro or in vivo. We previously reported that poly-pronuclear (PPN; 3 or more pronuclei) pig eggs developed normally to the blastocyst stage despite having fewer inner cell mass cell numbers as compared to blastocysts derived from two-pronuclear (2PN) eggs. Here it is shown that most PPN pig eggs have abnormal cleavage patterns (having 3 or more cells) in the first cell division and retarded development of pronuclei prior to syngamy as compared to 2PN eggs. Most blastocysts (14 of 18) that developed from PPN eggs showed abnormal ploidy (were haploid, triploid, and tetraploid) whereas 20 of 22 blastocysts derived from 2PN embryos were diploid. The size and morphology of most Day 40 fetuses that developed from PPN eggs appeared to be normal. Of 8 Day 40 fetuses analyzed, 1 was triploid (XXY) and another was a mosaic with both diploid (XX) and tetraploid cells (frequency of less than 10%, XXXX), and the others were diploid. Anomalies of chromosomal composition were not detected in these fetuses. Five live piglets and one dead piglet were born from two recipients of PPN eggs. It is proposed that not all pronuclei of PPN pig eggs participate in syngamy, resulting in diploid cells in the conceptus. Our data suggest that there are two types of pronuclei location in polyspermic pig eggs and that the resulting ploidy is determined at the zygote stage before the first cell division according to pronuclear location.

Triploidy: antenatal sonographic features with post-mortem correlation

A retrospective study was performed comparing the antenatal ultrasound (US) scan features with post-mortem findings in 20 triploid fetuses surviving beyond the first trimester. US scans showed a range of abnormalities including oligohydramnios (60 per cent of cases), intra-uterine growth retardation (IUGR, 55 per cent), central nervous system (CNS) abnormalities (45 per cent), and placental abnormalities (55 per cent). There were obstetric complications in 30 per cent of cases. Post-mortem examinations confirmed these findings but also demonstrated additional anomalies including facial dysmorphism, limb abnormalities (syndactyly, talips equinovarus and thigh muscle hypertrophy), and anomalies of cardio-vascular, respiratory and genito-urinary system. The placenta was normal in 16 per cent of cases, enlarged with cystic change in 47 per cent, small in 32 per cent and infarcted in 5 per cent of cases. Various factors including oligohydramnios, abnormal fetal position, less sophisticated equipment in mid-1980s and relative inexperience of early observers contributed to the reduced sensitivity of US scans in diagnosis of various defects. However, triploidy should be considered in all cases showing early second-trimester IUGR with or without oligohydramnios, a major CNS abnormality and/or an enlarged placenta with or without changes of partial hydatidiform mole. As triploidy is associated with increased obstetric complications, fetal karyotyping should be offered to confirm the diagnosis so that appropriate obstetric intervention can be instituted.

Chromosomally abnormal early ongoing pregnancies: correlation of ultrasound and placental histological findings

The pathophysiology of placental microscopic changes in chromosomally abnormal pregnancies remains poorly understood. We have reviewed the relationship between ultrasound findings and villous histological features in a group of 25 ongoing pregnancies presenting with fetal aneuploidy at 11 to 15 weeks of gestation. The chromosomal abnormalities were diagnosed by chorion villous sampling, and the data were compared with those of a group of 25 chromosomally normal pregnancies undergoing surgical termination and matched for gestational age. The aneuploid group included 10 pregnancies with trisomy 21, nine with trisomy 18, three with triploidy, two with monosomy X, and one with trisomy 13. The overall degree of agreement between the two investigators for the histological diagnosis was good (kappa, 0.64), and the sensitivity of histology ranged between 72.0% and 80.0%. Fetal and placental edema was observed on scan in 10 and 7 cases, respectively, of the aneuploid group and was systematically associated with trophoblastic hypoplasia, stromal edema, or cavitation, reduced vascularization, and ramification of the main villous trunks. Fetoplacental hydrops was not observed in the euploid group. These findings indicate that histological changes observed in the placenta of fetuses from ongoing pregnancies presenting with aneuploidy can be linked with early fetal hydrops. The villous features in these cases are probably secondary to a reduction in the villous circulation due to a cardiovascular defect and leading to generalized stromal edema. The reduced villous branching and trophoblastic hypoplasia could be secondary to the enlargement of all villous types or to a basic defect in placental development.

In routine diagnostic practice, how many sections should we examine from cases of products of conception?

In order to determine whether a single representative section taken from routine specimens of products of conception would contain sufficient material to trigger a more comprehensive search for the features of a hydatidiform mole, cases of gestational trophoblastic disease submitted over a five year period were reviewed. Partial hydatidiform moles were either suspected or diagnosed on the first histological section in 46 (92%) cases. In the remaining four cases, although abundant placental tissue showing diagnostic features was available in later blocks, most of the tissue in the first block consisted of endometrial tissue with only occasional chorionic villi being identified. The current study shows that a molar gestation can be suspected after examining a single tissue block, providing that it contains a representative number of chorionic villi. If a molar pregnancy is suspected clinically or pathologically, additional blocks should be examined to secure the diagnosis and classify the condition.

Interphase cytogenetic and AgNOR analyses of hydatidiform moles

AIM

To determine the potential value of interphase cytogenetic and argyrophilic nucleolar organiser region (AgNOR) analyses in the diagnosis and classification of hydatidiform moles.

METHODS

Serial tissue sections from 37 hydatidiform moles, histologically classified as 11 complete and 15 partial, and from 11 hydropic abortuses were examined by in situ hybridisation using digoxigenin labelled probes specific for chromosomes 1, X, and Y, and a one step silver staining method. The percentages of diploid and triploid nuclei, and the mean number of AgNORs for each tissue were determined.

RESULTS

Interphase cytogenetics showed that eight of the 11 cases (73%) each of complete mole and hydropic abortus had diploid pattern and the three remaining cases (27%) of each group were triploid. Two of the triploid complete moles and one of the triploid hydropic abortuses were revised to partial moles and one remaining triploid complete mole was revised to hydropic abortus. Of the 15 partial moles, nine (60%) were triploid, and six (40%) were diploid. These diploid cases were revised to three complete moles and three hydropic abortuses. There was a significant difference (p < 0.0001) between the mean (SD) AgNOR count in partial mole (5.11 (0.91)) versus hydropic abortus (3.79 (0.90)) and complete mole (3.39 (0.97)). The total of 15 triploid cases showed a high mean AgNOR count of 5.24 (0.73). Also, after reclassification, eight of the nine partial moles (89%) had a mean AgNOR count of > or = 5. The results of analyses by the two methods were closely correlated.

CONCLUSIONS

Interphasecytogeneticanalysis using chromosome specific probes and AgNOR count provides a valuable approach for ploidy analysis in histological sections of hydatidiform moles and helps to resolve difficult cases.

Prevalence of the partial molar phenotype in triploidy of maternal and paternal origin

Triploid partial moles are at risk for trophoblastic neoplasia, yet the prevalence, parent of origin, and evolution of the partial molar phenotype amongst all triploids remains controversial. We determined parental origin by polymerase chain reaction (PCR) analysis, stage of development by gross and histological criteria, and partial molar status according to strict diagnostic criteria for all triploids identified amongst 1,054 consecutively karyotyped spontaneous abortions. Triploidy was detected in 64 of 832 successfully karyotyped specimens. Complete data were collected in 59 cases. Diandric origin was found in 39 specimens, and 20 of these fulfilled all four criteria for partial mole (trophoblast hyperplasia, dimorphic population of large and small villi, villous hydrops greater than 0.5 mm, and irregular villous contour). We separated the 19 diandric triploids not fulfilling all criteria for partial mole into four groups: specimens of early developmental stage, which we believed represented developing ("early") partial moles (n = 3), cases of late developmental stage, which we believed represented involuting ("ancient") partial moles (n = 4), cases showing some but not all criteria for partial mole (n = 7), and specimens with few if any criteria suggestive of partial mole (n = 5). In triploids of digynic origin (n = 20), developmental stage was significantly lower, fetal tissue was more frequently identified, and all specimens showed well-preserved fetal red blood cells. Digynic triploids occasionally showed irregular contour, dimorphic villi, and a mild form of trophoblast hyperplasia but never showed hydropic degeneration and were never suspicious for partial mole.

Early prenatal diagnosis of triploidy

OBJECTIVE

Our purpose was to investigate the role of ultrasonography and maternal serum human chorionic gonadotropin in the early prenatal diagnosis of triploid pregnancies.

STUDY DESIGN

A retrospective study on 61,314 consecutive singleton pregnancies examined by ultrasonography at 10 to 14 weeks' gestation was performed to identify the prenatal features of those complicated by triploidy. When available, the serum human chorionic gonadotropin level was measured and ascertained retrospectively. Cases lost to follow-up or for which no karyotype was available were excluded from the final analysis.

RESULTS

Overall there were 18 cases of triploidy identified in a population of 58,862 singleton pregnancies, giving a prevalence of 1 in 3270. Fetal defects were observed in 8 (44.4%) of these cases; these included holoprosencephaly (n = 4), exomphalos (n = 3), and posterior fossa cyst (n = 1). In 6 (33.3%) cases the placenta showed molar changes. The fetal crown-rump length was below the 5th percentile in 10 of the 16 (62.5%) cases for which the menstrual age was also available. Fetal nuchal translucency thickness was above the 95th percentile in 12 (66.7%) cases, and the fetal heart rate was below the 5th percentile in 4 of the 13 (30.8%) cases evaluated. The maternal human chorionic gonadotropin level was high in 11 of the 13 (84.6%) cases tested, with similar distribution of the high values in molar and nonmolar triploidies.

CONCLUSION

The combination of ultrasonographic examination of the fetoplacental features and measurement of the maternal serum level of human chorionic gonadotropin enables the diagnosis of most cases of triploidy at 10 to 14 weeks' gestation.

Diploid hydatidiform moles with fetal red blood cells in molar villi. 1--Pathology, incidence, and prognosis

It is believed that fetal development does not occur in complete mole (CM); when present, it is usually interpreted as proof of partial mole (PM), in most cases a triploid conception with a low incidence of persistent trophoblastic disease (PTD). However, histological examination of 3180 moles in 8 years showed 60 moles (1.8 per cent) with features of CM and either embryonic tissues or amnion in the sample. Flow cytometry (FC) in 40 showed diploid complement in all. In ten of the 40, there was evidence of a twin; in 17, there was only amnion, which could belong to a twin; in the remaining 13, there was no evidence of a twin and nucleated fetal red blood cells (FRCs) were seen within molar vessels in ten (0.3 per cent). Seven of the 40 patients (17.5 per cent) and one of the ten with FRCs in villi (10 per cent) developed PTD, an incidence comparable to that of CM. Genetic studies in seven of these tea are reported separately. Finding fetal tissues with a mole or FRCs in molar vessels is not enough to classify it as PM, since it can be a CM with a twin, fetal development CM, or possibly a third type of mole. These rare diploid moles with fetal tissues have histological appearances and prognosis similar to those of CM.

Placental pathology of triploidy

Triploidy is a common chromosome abnormality in spontaneous abortions. Previous studies of spontaneous abortions have suggested that approximately 85% of triploid abortuses show the placental changes of partial hydatidiform mole (PHM) and that this appearance was associated, possibly attributable, to paternal origin of the extra haploid set of chromosomes. More recent work, however, has shown that most triploidy is the result of digyny--the extra set of chromosomes originating from the mother. Given the association of PHM with diandry, these results would appear to be at odds with the results of previous studies of placental morphology in triploids. The authors reviewed the placental pathology of all cases of triploidy examined at their institution over a 2-year period and established that PHM occurs in a minority of triploid conceptuses. These results support the findings of studies showing that digyny is the most common origin of triploidy.

Comparison of ploidy analysis by flow cytometry and image analysis in hydatidiform mole and non-molar abortion

Determination of DNA ploidy is useful in the diagnosis and classification of hydatidiform mole. Most reports of ploidy analysis in molar tissue have used DNA flow cytometry. Although image analysis cytometry offers theoretical advantages over flow cytometry, there have been few reports of ploidy analysis by image analysis in hydatidiform mole. We selected 47 cases and measured DNA ploidy by flow cytometry and image analysis cytometry in complete hydatidiform mole, partial hydatidiform mole and non-molar abortion. The two cytometry modalities were compared using kappa statistics. There was reasonable overall agreement between the two modalities (kappa = 0.69) and when ploidy was stratified into diploid/polyploid and triploid categories there was near perfect agreement (kappa = 0.93). Aneuploid cell populations, which were not evident on flow cytometry, were identified by image analysis in a significant proportion of complete and partial hydatidiform moles and in a small number of non-molar abortions. Flow cytometry and image analysis cytometry yield comparable ploidy information, useful in the diagnosis and classification of hydatidiform mole. Image analysis cytometry offers greater sensitivity in the detection of small non-diploid cell populations but the significance of this latter finding is uncertain.

Twin pregnancies with complete hydatidiform mole and coexisting fetus: use of fluorescent in situ hybridization to evaluate placental X- and Y-chromosomal content

Twin pregnancies with a complete hydatidiform mole (CHM) and a coexisting fetus have an aggressive postevacuation behavior; it is, therefore, important to differentiate these cases from partial hydatidiform moles that rarely require treatment for late sequelae. It has been presumed that twin pregnancies with a CHM and a coexistent fetus are dizygotic gestations, but this has not been confirmed in most cases. The authors investigated the sex chromosomal constitution of paraffin-embedded, formalin-fixed placental tissues in nine pregnancies histopathologically diagnosed as twin gestations with CHM and coexisting fetus, using fluorescent in situ hybridization (FISH) with X- and Y-chromosomal probes. Normal placental tissues showed an even sex distribution--four cases: X signal only, presumably female; four cases: X and Y signals, presumably male. In contrast, all molar tissues of these same pregnancies hybridized with the X-chromosomal probe only. Thus, in four of nine cases, gender differences (ie, different sex chromosome content) in molar villi (X chromosome only, cytogenetic female) versus normal villi (both sex chromosomes, cytogenetic male) confirmed the histopathological diagnosis of dizygotic twinning; a strict relationship between villous morphology (molar vs normal) and chromosomal gender was observed in each instance. This study illustrates that use of FISH on paraffin-embedded tissues can retrospectively establish dizygotic twinning in this unusual type of molar gestation.

Sad fetus syndrome--gestational trophoblastic disease concurrent with a living fetus or fetuses

The term gestational trophoblastic disease is used to indicate a group of both benign and malignant trophoblast, including molar degeneration of villi, hydatid mole, invasive mole and choriocarcinoma. This study shows a new classification of trophoblastic disease existing with a living fetus or fetuses. Benign hydatid mole is the initial stage of the disease continuum, whereas highly malignant choriocarcinoma is the final stage of this spectrum.

Incidence of hydatidiform mole in a Tokyo hospital: a 5-year (1989 to 1993) prospective, morphological, and flow cytometric study

This prospective study reports the incidence of hydatidiform mole (HM) in a population of 13,510 pregnancies in a Tokyo hospital over a 5-year period between 1989 and 1993. During this period all "products of conception" from first- and second-trimester abortions were histologically reviewed, and 76 hydropic placentas were retrieved and analyzed by flow cytometry (FCM). Of 23 specimens originally diagnosed as complete hydatidiform mole (CM), 21 were diploid, and two were aneuploid (nontriploid/tetraploid). Of 22 partial hydatidiform moles (PMs), 20 were triploid, and two were diploid. Of 31 hydropic abortions (HAs), 20 were diploid, nine were triploid, one was tetraploid, and one was aneuploid. As to the correlation between morphology and data of FCM, two PMs were reclassified as HA, and eight HAs as PM, giving a ratio of 1 CM to 1.22 PM (23:28 cases). The incidence of HM was 1:265 pregnancies, (CM, 1:587; PM, 1:483). Only one case (3.6%) of PM was suspected clinically. One specimen of persistent disease occurred following a diploid CM. In our retrospective histological and FCM study in which 172 cases diagnosed as HM were retrieved from surgical pathology files between 1981 and 1991, there were 129 CMs and 43 PMs (CMs:PMs = 3:1). These findings indicate that PM is a common but underdiagnosed condition. Almost all studies in the literature may have severely underreported the incidence of PM. It is suggested that during routine delivery and pathology examination only the most florid PMs are recognized, whereas most with subtler changes go undiagnosed.(ABSTRACT TRUNCATED AT 250 WORDS)

Ploidy analysis by flow cytometry and fluorescence in situ hybridization in hydropic placentas and gestational trophoblastic disease

Placentas with hydropic change may be hydropic degeneration (HD) or gestational trophoblastic disease (GTD), partial (PM) or complete (CM) hydatidiform mole. The separation of HD from PM and PM from CM by histological findings may be problematic in some cases and can be clarified with ploidy analysis. Fluorescence in situ hybridization (FISH) using a probe to chromosome 7 (D7Z1) was applied to tissue cut from paraffin blocks from 10 histologically representative cases each of HD, PM, and CM on which ploidy had been previously confirmed by flow cytometry from paraffin embedded tissue. Villous stromal cells and nonproliferative trophoblast were examined for number of signals/cell and percentage of cells/placenta with three hybridization signals. The mean number of hybridization signals/cell was HD 1.14; PM 1.79; and CM 1.17, with statistical significance between HD and PM (P < .0001), and PM and CM (P < .0001). The mean percentage of cells/placenta with three hybridization signals was HD 1.10%, PM 23.1%, and CM 2.11%, with statistical significance between HD and PM (P < .0001), and PM and CM (P < .0001). In addition, there was no overlap in the mean percentage of cells with three hybridization signals between HD and PM, and PM and CM. Chromosome 2 probe (D2Z1) was applied to tissues that had three chromosome 7 signals to exclude trisomy, and in all cases three signals were present confirming triploidy in PM. FISH can identify diploid and triploid hydropic placentas in paraffin-embedded tissue to assist in differentiating HD from PM, and PM from CM.