Human triploidy: association with partial hydatidiform moles and nonmolar conceptuses

Histopathologic study of partial hydatidiform moles and DNA triploid placentas

Sixty-two placentas with a triploid DNA content, which were analyzed by flow cytometry using paraffin-embedded tissues, were histologically investigated. These placentas were histologically classified as follows: 51 partial hydatidiform moles (PM), two hydropic abortuses and nine non-hydropic placentas. The DNA indices of the triploid peaks were between 1.41 and 1.60. Histologically, two populations of normal and edematous villi, vesicular villous edema with cistern formation, focal syncytiotrophoblastic hyperplasia with vacuolation, and villous scalloping with trophoblastic inclusion were almost always observed in the PM, but no single pathologic feature was specific for PM. The two entities, PM and triploid placenta, overlapped. Not all triploid gestations are PM and not all PM moles are triploid as shown in previously reported diploid or tetraploid PM. Although no patient with triploid PM developed persistent disease in this series, follow up of triploid PM is required as long as its true biological potential remains unclear. Flow cytometry is a reliable aid in the diagnosis of PM.

Genetic analysis of hydatidiform moles utilizing the oligonucleotide-DNA typing of the HLA-DRB gene

The genetic origin of hydatidiform moles was analysed utilizing HLA-DNA typing. Using HLA-DR type-specific oligonucleotide probes, the DRB types of seven moles were determined and compared with the parental DRB types to determine the paternal and/or maternal origin of the moles. In four cases, the molar tissues showed single DRB types of paternal origin, although in one, the molar DRB type was also possessed by the mother. These four moles were, therefore, considered to be androgenetic in origin. Chromosomal karyotyping was carried out for three of these cases and confirmed the DR-DNA typing results. Two moles demonstrated a DRB-type triplet, which strongly suggested triploidy. Although one mole showed a heterozygous DRB type, karyotyping indicated triploidy (69, XXX) and suggested that this mole was caused by dispermy-fertilization, in which both of the sperms had the same DRB type. Although the majority (about 80%) of partial hydatidiform moles have been reported to be triploid as a result of dispermy, four of the moles analysed in this study (cases 1, 2, 3 and 4), diagnosed as partial macroscopically and/or histopathologically, were found to be androgenetic in origin using karyotyping and DR-DNA typing. Therefore, HLA-DR DNA typing, combined in some cases with karyotyping, provides an accurate method for diagnosing androgenesis and triploidy in complete and partial hydatidiform moles.

Distinctive flow histogram pattern in molar pregnancies with elevated maternal serum human chorionic gonadotropin levels

BACKGROUND

Flow cytometric analysis of trophoblastic tissue has shown that most partial hydatidiform moles (PMs) are triploid, whereas most complete moles (CMs) are diploid or tetraploid. Ploidy analysis can support a diagnosis of CM or PM. However, in some cases, a precise diagnosis cannot be rendered.

METHODS

This study examined DNA flow histograms in 86 cases of histologically diagnosed moles and nonmoles to identify patterns specific to moles to eliminate indeterminate diagnoses. Forty hydropic abortions, 17 CMs, and 29 PMs were analyzed, and results were correlated with microscopic appearance and maternal serum human chorionic gonadotropin (HCG) levels.

RESULTS

Analysis of nondiploid histologic moles in which the initial maternal serum HCG level was greater than 150,000 mIU/ml showed similar histograms in 12 of 14 cases. In these 12 specimens, a distinct aneuploid peak could not be delineated from multiple cell populations between the G0/G1 and G2/M or G0/G1diploid and G0/G1aneuploid peaks. This commonly appeared as a slope rising toward the tetraploid region. S-phase fraction values showed a trend toward higher values in the moles versus nonmoles, but the difference was not statistically significant.

CONCLUSIONS

This sloping histogram pattern may reflect progression from a single aneuploid to multiple aneuploid populations. Its statistically significant correlation (P < 0.001) with high maternal serum HCG values suggests the presence of a highly metabolically active population of aneuploid trophoblast. Because it appears specific to nondiploid moles, recognition of the pattern will aid in the distinction of mole from hydropic spontaneous abortion.

Persistent gestational trophoblastic tumour with partial hydatidiform mole as the antecedent pregnancy

OBJECTIVE

A 16 year review of persistent gestational trophoblastic tumour when the antecedent pregnancy was a partial hydatidiform mole.

DESIGN

Cases of persistent gestational trophoblastic tumour with partial hydatidiform mole as the antecedent pregnancy were reviewed for the period 1976 to 1992. DNA ploidy was analysed by flow cytometry.

SETTING

A University Hospital which is a reference centre for gestational trophoblastic tumour.

SUBJECTS

The case notes of 207 women with persistent gestational trophoblastic tumour were reviewed.

MAIN OUTCOME MEASURES

A rise (or failure to fall) of beta hCG titre, or sign of metastasis.

RESULTS

Six (2.9%) women had partial hydatidiform mole as the antecedent pregnancy and all were initially judged to be low risk. However, two developed pulmonary metastasis; one woman developed persistent gestational trophoblastic tumour shortly after a hysterotomy, and none developed choriocarcinoma. The geometric mean of serum beta hCG concentrations at the initiation of chemotherapy was 868 mIU/ml (95% CI 114-1524). Of the six women, one achieved remission after total abdominal hysterectomy, and five after chemotherapy. The mean interval from starting treatment to remission was 68 days (95% CI 27.9-108.0). The initial beta hCG titre and interval were not statistically different from those found in cases of persistent gestational trophoblastic tumour when the antecedent pregnancy was not partial hydatidiform mole. Of the six, the DNA content was triploid in three and diploid in two. One of the two diploid cases required multiple courses of chemotherapy to achieve remission.

CONCLUSION

Partial hydatidiform mole can have malignant sequelae and can develop very soon after treatment. Its DNA content can be either diploid or triploid, the lungs being the most common site of metastasis. After evacuation of partial hydatidiform mole, immediate chest X-ray and regular follow up of the serum beta hCG level is necessary.

A morphometric approach to the relation of karyotype, gestational age and histological features in early spontaneous abortions

Previous studies revealed that chorionic villus size and proliferation of trophoblast were of little value as predictors of chromosomal abnormality. Since these findings might be due to the known intra- and inter-observer variation in histological assessments of early placentae, objective measurement of features might be more valuable to predict abnormal karyotype. Also, gestational age might influence structural development of villi in different karyotypes in a variable way, obscuring a possible relationship between features and karyotype. We, therefore, quantified villus size composed of stromal and trophoblastic tissues in 82 placentae using the point counting method and related the results to karyotype and gestational age. At the group level there appeared to be no difference in the median mean cross-sectional villus-, stromal and trophoblastic area, trophoblast/stroma ratio and trophoblastic thickness between chromosomally normal and abnormal placentae. Of the abnormal placentae only triploid placentae showed areas larger than normal and other abnormal placentae. In respect of gestational age villous profile area increased with age in triploid placentae, but decreased in trisomic abortions. At the individual case level parameter values outside the 'normal' range appeared to be rather insensitive, but highly specific for the prediction of karyotypic aberrations, again mainly triploidy.

Genomic imprinting: a new mechanism for disease

Evidence has been accumulating from various fields of research that genomic imprinting, defined as the differential modification of genetic material depending on whether inheritance is from the male or female parent, occurs in mammals as well as in man. Human genetic diseases such as complete hydatidiform moles, triploidy, Prader-Willi syndrome, Angelman syndrome, and various cancers provide strong support for the important role of genomic imprinting in human development and represents a new mechanism for disease.

Parental origin of triploidy in human fetuses: evidence for genomic imprinting

Two distinct phenotypes of triploid fetuses have been previously described and a correlation with parental origin of the triploidy has been suggested. We have studied the parental origin of the extra haploid set of chromosomes in nine triploid fetuses using analysis of DNA polymorphisms at a variety of loci. Maternal origin of the triploidy (digyny) was demonstrated in six fetuses with type II phenotype, paternal origin (diandry) in two cases with type I phenotype, and nonpaternity in one case. The predominance of digynic triploids in our study contrasts with the results reported in previous studies in which, through analysis of cytogenetic polymorphisms, paternal origin was found to account for the majority of triploid conceptuses. This difference may be accounted for by a combination of factors--the different methods of parental assignment used and analysis of a different subset of triploid conceptuses. The correlation between the observed phenotypes and the parental origin of triploidy may represent another example of imprinting in human development.

Can histopathologists reliably diagnose molar pregnancy?

AIMS

To assess the degree of difficulty in diagnosing partial mole by analysing intraobserver and interobserver agreement among a group of pathologists for these diagnoses.

METHODS

Fifty mixed cases of partial mole, complete mole, and non-molar pregnancy were submitted to seven histopathologists, two of whom are expert gynaecological pathologists; the other five were district general hospital consultants, one of whom works in Australia. These participants gave each slide a firm diagnosis of either partial mole, complete mole, or non-molar pregnancy. Some 12 months later, the slides were recorded and again submitted for a second diagnostic round to assess intraobserver as well as interobserver agreement. Standard histological criteria for each diagnostic category were circulated with the slides.

RESULTS

kappa statistics showed that complete mole could be reliably distinguished from non-molar pregnancy, but neither non-molar pregnancy nor complete mole could be easily differentiated from partial mole. In only 35 out of 50 cases was there agreement between five or more of the seven participants. Agreement between the expert gynaecological pathologists was no better than for others in the group. Interestingly, the intraobserver agreement for each pathologist was good to excellent.

CONCLUSIONS

These results imply that the reported histological criteria are either not being applied consistently or that they are lacking in practical use. An atypical growth pattern of trophoblast, rather than the polar accentuation seen in normal first trimester pregnancies, seems to be the important diagnostic histological feature for partial mole. Ploidy studies might also help with problem cases.

DNA cytometric and interphase cytogenetic analyses of paraffin-embedded hydatidiform moles and hydropic abortions

The combined application of DNA cytometric and interphase cytogenetic analyses was used to find objective criteria for the differential diagnosis of complete hydatidiform mole, partial hydatidiform mole and hydropic abortion. DNA ploidy and G0/G1 exceeding rates were determined using image and flow cytometric analyses on paraffin-embedded tissues of 166 cases: 71 cases of complete mole, 20 cases of partial mole, and 75 cases of abortions. To determine the existence and histological distribution of cell subpopulations with numerical chromosome aberrations, interphase cytogenetic analysis using probes specific for chromosomes 1, X, and Y was applied to paraffin tissue sections of 23 cases: 12 cases of complete mole, 3 cases of partial mole, and 8 cases of abortions. In contrast to previously reported findings that complete moles are diploid, the results of this study showed that complete moles are DNA-polyploid (96 per cent), with high G0/G1 exceeding rates and a high frequency of numerical chromosomal aberrations in the trophoblast hyperplasia. The majority of the partial moles were DNA-triploid (55 per cent). This study, however, also showed the presence of DNA-polyploid partial moles (30 per cent). Abortions were DNA-diploid (60 per cent) or DNA-triploid (39 per cent). DNA cytometric analysis, especially image DNA cytometric analysis with determination of the G0/G1 exceeding rate, and interphase cytogenetic analysis provide objective measurements which are contributory in the differential diagnosis between complete mole, partial mole, and hydropic abortion.

The value of histomorphological features of chorionic villi in early spontaneous abortion for the prediction of karyotype

This study was conducted to evaluate the value of histomorphological features of chorionic villi, such as size, shape, vascularity, trophoblast proliferation and trophoblastic pseudo-inclusions, for the prediction of chromosomal abnormality. Slides of 83 early spontaneous abortions were assessed by three observers. Assessments and karyotype were compared and likelihood ratios computed. Likelihood ratios of < or = 0.40 or > or = 2.50 were not obtained by all three observers for any of the features. One or two observers obtained likelihood ratios of > or = 2.50 for lacunar stromal hydrops, presence of trophoblastic hyperplasia, moderate to abundant trophoblastic hyperplasia, presence of trophoblastic lacunae, few intervillous fibrin deposits and few intervillous trophoblastic buds. Likelihood ratios of < or = 0.40 were found for small chorionic villi and presence of basophilic staining. Lacunar stromal hydrops and trophoblastic lacunae were predictive of triploid karyotype, but not specific for any other type of chromosomal abnormality. After application of data previously obtained on Cohen kappas, lacunar stromal hydrops, moderate to abundant trophoblastic hyperplasia and presence of trophoblastic lacunae remained as possibly useful features, again mainly for identifying triploidy. Most of the items claimed to be related to abnormal karyotype, however, were not predictive at all.

Intra- and inter-observer variation in the interpretation of histological features suggesting chromosomal abnormality in early abortion specimens

Early spontaneous abortion is a common phenomenon, with more than 50% of early cases showing chromosomal abnormalities. We have undertaken a study to evaluate intra- and inter-observer reproducibility of histological diagnoses of features associated with chromosomal abnormalities, such as chorionic villus size, shape, vascularity, trophoblastic proliferation and trophoblastic pseudo-inclusions. The intra-observer variation for most histological features was small. However, the agreement beyond chance between two or more observers in judging histomorphological features of early abortion placentae only reached clinically relevant values for size and shape of the chorionic villi and for the number of trophoblastic pseudo-inclusions.

Diagnostic considerations in molar gestations

Hydatidiform moles (HMs) are classified as partial or complete based on a combination of gross, histologic, and karyotypic features. Adherence to strict and reproducible diagnostic criteria is needed to ensure accurate diagnosis and minimize interpathologist variability. Using the kappa statistic as a measure of agreement, the morphologic, flow cytometric, and clinical features of 80 cases of HM or suspected HM were analyzed sequentially by three pathologists to evaluate intrapathologist and interpathologist variability. Poor interpathologist agreement was obtained when histology alone was used for diagnosis. The combination of gross morphology and histology resulted in poor to good agreement. Good interpathologist agreement was obtained, however, when objective data (DNA content determined by flow cytometry) were included in the analysis. Our data indicate that pathologist concordance is maximized when the diagnosis is based on a combination of morphology and DNA content.

Recurrent consecutive partial molar pregnancy

Gestational trophoblastic disease (GTD) is rare. Recurrent GTD, though occurring in only 0.6-2.6% of subsequent pregnancies, has significant clinicopathological implications. These include risk of malignant sequelae and subsequent poor reproductive performance. The cytogenetics and histopathology of complete and partial moles differ, yet there are several clinicopathological similarities. Although complete hydatidiform moles are known to recur, very little is known about recurrent partial vesicular moles in world literature. We report here on a patient with four consecutive recurrent partial hydatidiform moles who is yet to achieve a normal pregnancy. Her third molar pregnancy was further complicated by severe thyrotoxicosis. The unusual histology and the progressively more aggressive clinical course are discussed. The small risk of malignant sequelae and the need for close endocrinological monitoring are highlighted, as are her chances of yet another recurrent GTD.

Flow cytometric studies in spontaneous abortions. Applications in the medico-legal practice

In the medico-legal practice differential diagnosis between spontaneous and non-spontaneous abortion is important because causes of pregnancy wastage are often obscure and, moreover, spontaneous abortion is more common than accidental or voluntary. In all the cases in which the cause of abortion is not otherwise detectable and especially in cases of discovery of fetal adnexa, it is necessary to investigate genetic causes. Recently, DNA flow cytometric analysis has been applied in determining the genetic causes of spontaneous abortions. Among karyotypic abnormalities, flow cytometric analysis on paraffin embedded material can detect only polyploidies (triploidy and tetraploidy). Trisomies, monosomies and structural anomalies cannot be detected. In our study we tried to establish whether flow cytometry could be useful in determining the genetic cause of spontaneous abortions, in the lack of any other detectable cause. Histologic examination and flow cytometric analysis were performed on a series of 395 consecutive spontaneous abortions. Histologic examination allowed the detection of a molar pattern in about 9% of cases. DNA flow cytometric analysis showed diploidy in 346 (87.59%) cases, triploidy in 37 (9.36%) cases and tetraploidy in 12 (3.03%) cases. Combined microscopic and flow cytometric analysis revealed abnormalities in 17.5% of cases. A non-diploid pattern is more frequent in molar cases (P less than 0.001). Flow cytometry seems to be interesting in forensic pathology, as it allows the detection of some frequent genetic abnormalities in dead tissues and cells, when other techniques are no longer practicable.

Argyrophilic nucleolar organizer regions in breast carcinoma. Correlation with DNA flow cytometry, histopathology, and lymph node status

Argyrophilic nucleolar organizer regions (AgNOR) have been correlated with proliferative activity of neoplasms. Increased AgNOR may reflect increased proliferative activity of cells or ploidy. To explore this hypothesis, 41 breast carcinomas were processed for AgNOR silver staining and DNA flow cytometry. AgNOR counts were expressed as mean AgNOR/nucleus and percentage of tumor cells with more than five AgNOR/nucleus. The first count was designated mean AgNOR or mAgNOR, and the second count was designated AgNOR proliferative index or pAgNOR. Using Mantel-Haensel statistical analysis, carcinomas that exhibited mAgNOR of 2.4 or more had a high likelihood of aneuploidy (P less than 0.0001), an S-phase fraction of more than 5.8% (P less than 0.003), or a diameter greater than 2 cm (P less than 0.007). In addition, tumors with pAgNOR of 8% or more showed a statistically significant correlation with aneuploidy (P less than 0.004), tumor grade (P less than 0.04), and a more significant one with high S-phase fraction (P less than 0.0001). No significant correlation was obtained between pAgNOR and tumor size or lymph node status. These data indicate that AgNOR quantitation reflects changes in DNA ploidy and cell proliferation. They also suggest that the mean AgNOR counts correlate best with the DNA mass or ploidy and that the frequency of cells with higher AgNOR count best reflects proliferative activity or S-phase fraction.

Two AgNOR counts in fine-needle aspirates of lymphoproliferative disorders compared with acridine orange flow cytometry

Studies have shown that argyrophilic nucleolar organizer region-associated proteins (AgNORs) may correlate with DNA ploidy and/or proliferative activity in neoplastic and non-neoplastic conditions. However, studies have estimated only the mean AgNOR counts. Here we used two AgNOR counts, one of which may correlate with DNA ploidy and the other with proliferative activity. The mean AgNOR count (mAgNOR) was defined as the mean number of AgNORs/nucleus in 100 cells and may represent DNA or RNA index. The percentage of nuclei exhibiting 5 or more AgNORs/nucleus (pAgNOR) may reflect proliferative activity. These two AgNOR counts were correlated with results from acridine orange flow cytometry in 50 fine-needle aspirate (FNA) smears of nodal and extranodal sites, including three cases of reactive lymphadenopathy and 47 cases of non-Hodgkin's lymphoma. The mean mAgNOR count in the diploid specimens was 2.03 (+/- 0.74 SD) and 2.62 (+/- 0.73 SD) in the aneuploid tumors (P less than 0.0001). Samples with a low RNA index had mean mAgNOR of 1.80 (+/- 0.41 SD), whereas those with high RNA had a mean mAgNOR of 2.93 (+/- 0.86 SD) (P less than 0.0001). Lesions with low proliferative index, determined by flow cytometry, had a mean pAgNOR of 4%, whereas those with intermediate and high proliferative indices had a mean pAgNOR of 16% (P less than 0.0001). A similar but less significant correlation existed between RI and pAgNOR (P less than 0.005). We conclude that the two AgNOR counting methods may reliably reflect cell kinetics and distinguish ploidy from proliferative activity, making them useful adjuncts to flow cytometry in limited cytology specimens and small biopsy samples.

Clinical application of flow cytometry for DNA analysis of solid tumors

Recent developments of flow cytometry (FCM) technology which make multiple correlative biological measurements on normal and neoplastic cells is affecting areas of diagnostic pathology as well as research fields, and a general understanding of FCM techniques is essential for pathologists. Today, FCM DNA measurements of tumors also becomes routine in the clinical and/or pathological laboratory for aid in cancer diagnosis and cancer treatment. It can also contribute to diagnosis of tumors as a supplemental method to conventional histopathology, and DNA ploidy and the percentage of S-phase fraction are considered as complementary prognostic parameters independent of the stage of disease. This article reviews clinical applications of flow cytometry focusing on the DNA measurements of solid tumors, and related practical issues, such as the methodology for nuclear DNA measurement, interpretation of DNA histograms and the relationship of DNA ploidy and S-phase fraction to clinical and pathological features of human solid tumors.

Persistent gestational trophoblastic disease following evacuation of a tetraploid partial hydatidiform mole

A 31-year-old woman at 11 weeks gestation with ultrasonographic demonstration of partial mole had markedly elevated serum bHCG levels (458,000 mIU/ml). The patient underwent a vacuum curettage with pathological confirmation of the diagnosis, and cytogenetic analysis revealed a tetraploid karyotype (92,XXXX). The patient developed persistent gestational trophoblastic disease and was successfully treated with two courses of actinomycin D. Persistent trophoblastic disease after evacuation of a tetraploid partial mole was not reported previously.

Interphase cytogenetics in paraffin sections of routinely processed hydatidiform moles and hydropic abortions

The differential diagnosis of complete (CM) and partial (PM) hydatidiform moles and hydropic abortions (HA) can be difficult when based on histology alone. Therefore, a more objective approach of chromosome ploidy analysis as detected by in situ hybridization (ISH) was performed on 6 microns paraffin sections of seven cases, originally classified as three CM, two PM, and two HA with a histologic pattern suggestive of triploidy. Probes for repetitive DNA targets in the (peri)centromeric region of chromosomes 1 and X and in the q arm of chromosome Y were used to determine chromosome ploidy and sex chromosome composition. The findings in the three CM were consistent with diploidy: two copies of chromosomes 1 and X and none of chromosome Y. In the two HA with a histologic pattern suggestive of triploidy, three copies of chromosomes 1 and X and none of chromosome Y confirmed triploidy. Two cases originally classified as PM both appeared to have two copies of chromosome 1 with an XX pattern in one case and an XY pattern in the other case, which is consistent with diploidy instead of triploidy. After reviewing, both cases most likely represented CM. We conclude that interphase cytogenetics by ISH on paraffin sections of hydatidiform moles and hydropic abortions enables chromosome ploidy analysis with preservation of histological context.(ABSTRACT TRUNCATED AT 250 WORDS)

Karyotype and placental structure of first-trimester spontaneous abortions: a morphometrical study

Size of placental villi, thickness and condition of trophoblast, stromal density of villi as well as perivillous fibrinoid deposits were used as criteria for patho-morphological classification of karyotyped first-trimester spontaneous abortions. Significant differences in all the criteria were noted. Diagnostic values were verified using discriminant analysis. Using morphological values, 67% of the cases could be grouped correctly. Including further criteria (week of gestation, age of mother) it was possible to improve this to 72%. Normal karotype and trisomy could be accurately diagnosed using morphology; however, it is not suitable for finding monosomy X and tetraploidy.

Triploidy arising from a first meiotic non-disjunction in a mother carrying a reciprocal translocation

We report on a 22 year old mother, a carrier of a 6;14 balanced reciprocal translocation, who aborted a triploid conceptus carrying a similar translocation. We showed the maternal origin of this triploidy, after non-disjunction at meiosis I. The phenotypic expression as a non-molar pregnancy, the contribution of the maternal translocation, and possible aetiological factors of triploidy are discussed.

Ultrasonographic assessment of placental abnormalities

Current ultrasonographic techniques offer a novel approach for the identification of a wide variety of placental abnormalities usually described postnatally by the pathologist. Placental vascular lesions, placental tumors, and abnormal placentation are potentially associated with perinatal complications and their diagnosis in utero may influence the pregnancy management. An ultrasonographic classification of placental lesions that is based on their location, size, echogenicity, and number is proposed. Repeated ultrasonographic examination, together with biologic investigations, is important for the prenatal differential diagnosis of most these lesions and for full understanding of their pathophysiologic characteristics and significance.

Triploidy syndrome in a liveborn female

We present the autopsy report of a liveborn triploid female, born after 36 weeks of gestation, who died at the age of 20 hours. External features were diagnostic: fetal hypoplasia, hypertelorism, microstomia, micro-and retrognathia, preauricular skin tag, low-set ears, and 3-4 syndactylia. All internal organs were hypoplastic. There were atrial and ventricular septal defects. Adrenals and kidneys were fused, the gallbladder was absent, and ovarian hilum cell were found to be hyperplastic. Triploidy, 69xxx, was confirmed cytogenetically. The placenta was hypoplastic and, microscopically, revealed a peculiar type of immaturity, so-called hydatidiform villous hypoplasia, findings which have not been previously reported. We suggest that the generalized fetal and placental hypoplasia and the severe hypoplasia of all internal organs are caused by a proliferative deficiency of the triploid cells. In addition, the nuclear DNA content was determined by cytophotometrically from placental stromal cells and was found to be about 50% above the normal diploid DNA value; i.e., a triploid DNA value was confirmed.

Surface and branching of placental villi in early abortion: relationship to karyotype. Scanning electron microscopic study

The placental villi of 61 early abortions with known karyotype and 7 legally induced abortions were investigated by scanning electron microscopy and documented in standardised enlargements. Five groups were established from the findings: uniformly branched villi with a velvety surface (group A) were found in 4 of the 7 induced abortions, abundant syncytial sprouts (group B) in 4 of the 6 cases with monosomy X; all 5 cases of triploidy were classified in the group bulbous or spherical villi (group C); 13 out of 25 cases of trisomy were found to have little branching and a surface densely covered with microvilli (group D), while 14 out of the 25 cases of euploidy belonged in the group with slender villi and surface with focal areas of denudation (group E). Forty of the 68 cases were properly assignable to the correct groups (58.8%). The non-uniformity of the villous morphology in the case of induced abortions shows that there is no uniform development of the (early) placenta. The variable morphology seen in abortions with euploidy reflects the various mechanisms of abortion applicable to this group.

Persistent gestational trophoblastic tumor after partial hydatidiform mole

The current study investigates the clinical characteristics of patients with partial molar pregnancy who developed persistent gestational trophoblastic tumor (GTT). Between January 1979 and January 1989, 16 of 240 (6.6%) patients, who were followed for partial mole, developed persistent GTT. Fifteen (94%) patients were diagnosed as having a missed abortion before evacuation and only 1 patient presented with excessive uterine size and theca lutein ovarian cysts and was felt to have molar disease. No patient presented with toxemia, hyperemesis, or hyperthyroidism. All 16 patients developed nonmetastatic GTT. Fifteen patients achieved complete remission with methotrexate-citrovorum factor and only 1 patient required combination chemotherapy to attain remission. None of the patients had histologic evidence of choriocarcinoma. Patients with partial mole who developed persistent GTT did not have clinical or pathological characteristics that distinguished them from other patients with partial mole. All patients with partial mole should be followed with measurement of hCG levels to assure gonadotropin remission.

Triploidy: pregnancy complications and clinical findings in seven cases

Seven cases of triploidy were encountered by the Prenatal Diagnosis Program at Dartmouth-Hitchcock Medical Center over an 8-year period through associated pregnancy complications. We describe the characteristic findings that facilitate prenatal diagnosis and management. Our experience includes fetuses with major central nervous system abnormalities (spina bifida aperta, holoprosencephaly) and anterior abdominal wall defects, which are detectable with routine prenatal diagnostic screening examinations (ultrasound and AFP). In addition, we stress the importance of recognizing obstetric complications and associated cystic placental changes, which are quite common among triploid conceptuses. Molar changes associated with triploidy have a more benign prognosis than that associated with diploid moles. Such molar changes may relate to the presence of a diploid paternal chromosome complement. The usefulness of cytofluorometric DNA determinations in helping to confirm a clinical suspicion of triploidy is emphasized. These cases are presented in an effort to facilitate prenatal recognition and management of this common cytogenetic condition and prevent unnecessary Caesarean section deliveries.

Prenatal ascertainment of triploidy by maternal serum alpha-fetoprotein screening

We report our experience in ascertaining fetal triploidy during routine maternal serum alpha-fetoprotein (MSAFP) screening. Three cases were identified after elevated MSAFP tests. Two of the three had normal amniotic fluid alpha-fetoprotein (AFAFP). The third had amniocentesis too late for AFAFP interpretation. Three additional cases were detected by amniocentesis without prior MSAFP screening and none had an elevated AFAFP. A literature review revealed eight triploid fetuses detected as a result of an elevated MSAFP. Of the five with AFAFP quantitation, only one had an abnormal value and the elevation was minimal. In these 14 cases from our own and other reports, ultrasound findings of placental and fetal abnormalities were often noted, but a pattern diagnostic of triploidy was not present. We conclude that, for optimal prenatal detection of triploidy, fetal karyotyping should be included when an amniocentesis is performed for elevated MSAFP.

The biology of tetraploid hydatidiform moles: histopathology, cytogenetics, and flow cytometry

We identified three cases of tetraploid hydatidiform moles (HM). A complete hydatidiform mole (CM) had a 92,XXXX karyotype. The two partial hydatidiform moles (PM) had karyotypes of 69,XXY/90,XXXY,-11,-13 and 92,XXYY, respectively. Study of chromosomal heteromorphisms in the 92,XXYY PM revealed two maternal and two paternal haploid sets. Flow cytometric analysis of nuclear DNA content from fresh placental tissue from the 69,XXY/90,XXXY,-11,-13 PM demonstrated distinct peaks in the triploid and tetraploid regions and an octaploid G2/M peak. Flow cytometric analysis of paraffin-embedded, fixed tissue was diagnostic of tetraploidy in the 92,XXXX CM and consistent with tetraploidy in the 92,XXYY PM. All three patients achieved spontaneous remission of elevated gonadotropin levels. These three cases of tetraploid HM do not fit into the usual patterns of diploid CM and triploid PM. We conclude that flow cytometric analysis of nuclear DNA may be used to identify polyploidy in fresh and paraffin-embedded, fixed placental tissues. Categorization of all molar placentas on the basis of ploidy presents rare opportunities to study the biology and natural history of gestational trophoblastic disease in tetraploid HM.

Molar pregnancy coexisting with a normal fetus: a case report

Molar pregnancy with a coexisting live fetus is a rare occurrence. We present morphologic and cytogenetic analysis of a recent case. Cytogenetic studies revealed a 46, XX karyotype for the fetus, the normal placenta, and the abnormal placenta. Chromosome banding studies confirmed the presence of maternal and paternal chromosomes in all three tissues. These studies favored the possibility that both tumor and fetus arose from a single gestation. Subsequently, the patient required chemotherapy for low-risk, metastatic trophoblastic disease.

The use of DNA flow cytometry in the diagnosis of triploidy in human abortions

The ploidy of placental tissue from 59 abortions was determined using DNA flow cytometry. The specimens were also screened histologically for features considered to be characteristic of a partial mole. Triploidy was found in six cases; three of these cases presented histologically as partial moles. From the four specimens histologically classified as partial moles, three appeared to be triploid. The most specific histologic features of triploidy were cystic change of the placental villi and trophoblastic hyperplasia with vacuolation of the syncytiotrophoblast; however, these changes were also found in some of the nontriploid abortions. Irregularity of villous contours was less specific.

The pathologist's perspective of genetic disease. Malformations and dysmorphology

The pathologic approach to the study of malformations and congenital abnormalities emphasizes the importance of careful dissection and pathologic studies. Concepts and terms of morphogenesis as defined by the International Working Group are presented. The developmental field is the central concept of a malformation. Malformation syndromes, disruptions, sequences, deformations, dysplasias, and associations are presented. The significance of fetal hydrops and short umbilical cord is discussed. Pathologic studies in chromosome defects suggest pathologic markers for some chromosome abnormalities.

Cardiac defects in chromosomally abnormal human embryos of 10-14 weeks' gestation

Cardiac defects were studied in five chromosomally abnormal embryos of 10-14 weeks' gestation by free-hand microdissection of hearts measuring 2.5-6 mm in diameter. The type of cardiac malformation alone or in association with other anomalies helped to confirm the chromosome diagnosis established prenatally by chorionic villus sampling or after spontaneous abortion. It was suggestive of a chromosomal disorder in one case in which cytogenetic investigation had failed.

Incidence and aetiology of hydatidiform mole: an epidemiological review

Epidemiological investigation of the incidence and aetiology of hydatidiform mole (HM) is receiving increasing attention. Recent, population-based studies suggest that earlier reports of a very high incidence of HM in Asia, Africa and South-Central America may have been exaggerated, due primarily to selection bias in patients studied at university hospitals. Japanese population studies indicate a two-fold higher rate of HM compared with Caucasian rates but Chinese rates appear to be similar. Population studies presently available suggest a worldwide range of HM somewhere between 0.5 and 2.5/1000 pregnancies. When deliveries form the rate denominator the rates are somewhat higher, depending primarily on the national rate of induced abortions. The independent effects on incidence of geographic locale, ethnicity and socio-cultural factors have not been adequately disentangled although the genetic studies suggest ethnicity might be the predominant variable. Maternal age is the most consistently demonstrated risk factor; teenagers and, especially, women over age 35 being at increased risk. The independent effects of paternal age and pregnancy history are not established. Women with a history of one HM seem to have a ten-fold risk of repeat HM compared with women who have no history of HM. Aetiological studies have not revealed any environmental risk factor for which there is unequivocal agreement about its influence on HM. New case-control studies of HM aetiology must classify HM according to genetic aetiology. Cohort studies are required to explore more fully the relation of HM to malignant sequelae.

Hydatidiform mole: cytogenetically unusual cases and their implications for the present classification

Unusual observations in hydatidiform moles are of clinical importance as well as of theoretical interest when the present subgrouping into partial or complete moles is evaluated, particularly in view of the more malignant potential of the latter. The purpose of the present review is to summarize, update, and evaluate information on moles with unusual karyotypes or origins. The important factor in the evolution of partial or complete moles appears to be the ratio of maternal to paternal chromosomes and not the ploidy of the tissue. Complete hydatidiform moles develop from androgenetic conceptions while partial hydatidiform moles develop from those conceptions in which the number of paternal sets of chromosomes exceeds the number of maternally derived sets. Rare cases inconsistent with this concept emphasize the value of examining morphologic features, cell ploidy, and genetic markers when one is attempting to classify hydatidiform moles.

Diagnosis of molar pregnancy and persistent trophoblastic disease by flow cytometry

Histopathological assessment and flow cytometric analyses were carried out on 32 placentas (representative of each trimester) and 88 molar pregnancies. Three first trimester placentas were triploid, and the remaining 29 placentas were diploid. Of the 88 cases originally diagnosed as molar pregnancies, 26 were triploid (two complete moles, 20 partial moles, and four hydropic abortions); 59 were diploid (46 complete moles, 10 partial moles, three hydropic abortions); one was tetraploid (partial mole); and two were DNA aneuploid (one partial mole, one complete mole). A significantly increased hyperdiploid fraction (a measure of cell proliferation) was detected in diploid complete moles (p less than 0.0001) and cases of persistent trophoblastic disease (p less than 0.001) when compared with diploid placentas and diploid partial moles. All seven cases of established persistent trophoblastic disease, for which follow up was available, were diploid and showed high hyperdiploid fractions within the range for diploid complete moles. These findings suggest that flow cytometric DNA measurements may be an important aid in the diagnosis of molar pregnancy. The high degree of cell proliferation found in this study may explain the premalignant potential of complete hydatidiform moles.

Hydatidiform mole coexisting with a live fetus: a dilemma of management. A recent review (1965-1985) and report of 2 new cases

A review of 24 patients with a molar placenta and coexisting live fetus, including 2 new cases from the Queensland Trophoblastic Disease Registry, was made. The rate of fetal abnormalities was 33%; all 8 abnormal fetuses were female and in 5 of them in whom cultures were performed the chromosomal karyotype was triploidy 69XXX. There were 3 patients in whom malignant sequelae were detected (12%). After a confident ultrasound diagnosis of a molar placenta and a coexisting live fetus, the decision on whether the pregnancy should be terminated or allowed to continue should be based on the likelihood of the fetus being abnormal. It is recommended that the chromosomal karyotype and amniotic fluid alpha-fetoprotein level be determined by amniocentesis at about 16-18 weeks. This should allow those pregnancies in whom the fetus is potentially normal to be selected for conservative management.

Tetraploid partial hydatidiform moles: two cases with a triple paternal contribution and a 92,XXXY karyotype

In the course of a systematic study of cytogenetics, morphology, and clinical follow-up of hydatidiform moles we encountered two unusual cases of partial hydatidiform moles each with a 92,XXXY karyotype. Previously reported cases of tetraploidy, of 92,XXXX or 92,XXYY karyotype, resulted from a failure of the first mitotic division of a normal zygote. This is to our knowledge the first report of tetraploidy with XXXY sex chromosomes. Study of chromosomal heteromorphisms, isozymes, and restriction fragment length polymorphisms reveal that both present cases resulted from a combination of a haploid ovum with three haploid sets of paternal chromosomes either by the mechanism of trispermy (involving three separate haploid spermatozoa) or through dispermy (involving one haploid and one diploid sperm). Both cases resembled closely partial moles in their morphology; one gave a highly typical clinical picture while the other was recognized at an early voluntary abortion. Partial moles are ordinarily triploids of nearly always diandric constitution that evince focal villous swelling with cistern formation and focal trophoblastic hyperplasia. The findings here presented point to an association of molar phenotype with an excess of paternal over maternal haploid sets.

Triploid embryo after in vitro fertilization

A case of a triploid embryo (69,XXX) resulting from in vitro fertilization is reported. The pregnancy ended in spontaneous abortion 44 days after embryo transfer. The embryo showed anomalies considered typical of triploidy but molar changes were not noted. The origin of extra chromosomes was apparently maternal.

Hydatidiform mole in Nottingham: a 12-year retrospective epidemiological and morphological study

The results of a 12-year retrospective study on the epidemiology of hydatidiform mole (HM) in Nottingham are presented. We have reviewed the histology of our cases of HM, tried to minimize selection bias, and have used the most reliable data available. Using data from two different sources we have calculated the frequency of HM as 1 in 1400 deliveries. The frequency of HM in this study is one quarter of that reported in an excellent study from Japan. We suggest that, with accurate epidemiological studies, the difference in frequency of HM between 'high risk' and 'low risk' areas is less than previously accepted. The present study also shows a lower incidence of persistent trophoblastic disease than previously generally accepted. We confirm that partial HM is a distinct clinicopathological entity and that two forms are distinguishable histologically. The malignant potential of partial HM is uncertain, and we suggest that the clinical management of partial HM should be no different from that of complete HM until further studies dictate otherwise.

Quantitative morphology. A study of the trophoblast

It is difficult to predict the possible development of a malignant trophoblastic tumor after the evacuation of a hydatidiform mole. In order to help resolve this difficulty, a morphometric study has been carried out. The mean nuclear area of the trophoblast in a group of hydatidiform moles, followed by a trophoblastic malignancy, was found to be statistically significantly larger than that of the trophoblast in a group of hydatidiform moles which were not followed by malignant trophoblastic disease. However, the mean trophoblast/nontrophoblast ratio in villi demonstrated no statistically significant difference between those 2 groups of hydatidiform moles. Therefore it is not advisable to grade hydatidiform moles on the basis of trophoblastic proliferation alone. It is suggested that the trophoblastic lining of hydropic villi in the placental tissue of hydatidiform moles has malignant features already, but these are more pronounced in those hydatidiform moles which are subsequently followed by a choriocarcinoma.