Histopathological diagnosis of hydatidiform mole: contemporary features and clinical implications

Clinical assessment of prophylactic chemotherapy in treating with hydatidiform mole: A protocol for systematic review and meta-analysis

BACKGROUND

Hydatidiform mole (HM) is more common as molar pregnancy. It is a disease classified under the category of gestational trophoblastic diseases, which could metastasize after originating in the placenta. A majority of females suffering from molar pregnancies are curable by evacuating retained products of conception and the patient's fertility is preserved. In some cases, the growth perseveres and leads to gestational trophoblastic neoplasia, which is an extremely malicious condition that needs chemo-based treatment. There is a possibility to lessen the risk of gestational trophoblastic disease in females with HM through the administration of prophylactic chemo. Yet, there is controversy regarding prophylactic chemotherapy administered pre-or-post removal of HM to curtail the malignant sequelae. Therefore, we will conduct this research to assess both the efficacy as well as security of using prophylactic chemotherapy to treat HM.

METHODS

In the preliminary review, the authors will search for randomized controlled trials involving prophylactic chemotherapy to treat HM. The literature search is carried out in the following electronic databases from their inception to May 2021: Chinese National Knowledge Infrastructure, Chinese BioMedical Literature, and WanFang database are the three Chinese language databases. Web of Science, PubMed, Cochrane Library, and EMBASE are the four English language databases. The authors will also perform a manual search through the bibliographies in related literature to find extra articles and ongoing studies. Two independent authors will assess the literature according to an inclusion criteria, use a specialized data collection table to extract data, and use the Cochrane 'Risk of bias' tool for evaluating any possible bias risk in the selected articles. Data synthesis and statistical operations are completed with the RevMan software (v. 5.3).

RESULTS

The present systematic analysis provides a rationalized synthesis of existing evidence related to the use of prophylactic chemotherapy in the treatment of HM.

CONCLUSION

Our findings will summarize the current evidences for prophylactic chemotherapy in the treatment of HM.

ETHICS AND DISSEMINATION

An ethics approval is nonrequired because pre published results will be used.

REGISTRATION NUMBER

DOI 10.17605/OSF.IO/6QV52 (https://osf.io/6qv52/).

Pathology of gestational trophoblastic disease (GTD)

Gestational trophoblastic disease (GTD) is subclassified into hydatidiform mole (HM), gestational trophoblastic tumours (GTT) and non-neoplastic trophoblastic lesions. HM, partial and complete, originate from villous trophoblast and are considered as preneoplastic conditions. The risk for the development of persistent GTD, mostly as invasive HM, ranges from 0.5% to 20%, which depends on the type of molar pregnancy. The risk of development of trophoblastic tumour after PHM is <0.5% and 2%-3% after CHM. GTT represent a spectrum of neoplasms that originates from the intermediate, largely extravillous, trophoblast and these include choriocarcinoma (CC), placental site trophoblastic tumour (PSTT), epithelioid trophoblastic tumour (ETT) and mixed trophoblastic tumour. Among tumour like conditions, exaggerated placental site reaction (EPSR) and placental site nodule (PSN) (s)/plaque (s) are included. The morphological appearances of HM can be mimicked by abnormal (non-molar) villous lesions, and similarly, GTT can be mimicked both by non-malignant tumour-like conditions and non-gestational tumours with trophoblastic differentiation, which add to the diagnostic dilemma of these rare conditions. GTT have a favourable prognosis and better response to specific chemotherapeutic regimens when compared with non-gestational malignant genital tract neoplasms. The correct diagnosis and classification of these rare conditions are therefore important. This article focusses on the morphological appearances, immunocytochemistry as an aid in the diagnosis and the changes in current WHO classification of GTDs (WHO 2020).

Genetics of gestational trophoblastic disease

The abnormal pregnancies complete and partial hydatidiform mole are genetically unusual, being associated with two copies of the paternal genome. Typical complete hydatidiform moles (CHMs) are diploid and androgenetic, while partial hydatidiform moles (PHMs) are diandric triploids. While diagnosis can usually be made on the basis of morphology, ancillary techniques that exploit their unusual genetic origin can be used to facilitate diagnosis. Genotyping and p57 immunostaining are now routinely used in the differential diagnosis of complete and partial hydatidiform moles, for investigating unusual mosaic or chimeric products of conception with a molar component and identifying the rare diploid, biparental HMs associated with an inherited predisposition to molar pregnancies. Genotyping also plays an important role in the differential diagnosis of gestational and non-gestational trophoblastic tumours and identification of the causative pregnancy where tumours are gestational. Recent developments include the use of cell-free DNA for non-invasive diagnosis of these conditions.

Decreasing incidence of registered hydatidiform moles in Denmark 1999-2014

Incidences of hydatidiform mole (HM) registered in European countries varies from 0.98/1000 to 2.17/1000 deliveries, while higher incidences have been reported in other parts of the world. We calculated the incidence by selecting data on HMs classified as ”first”, “second” and “third” from 01.01.1999 to 31.12.2014 registered in the Danish Pathology Registry, which we previously showed to be the most complete data source on the number of HMs in Denmark. In the study period, 1976 first HMs were registered; 1080 (55%) were classified as PHMs (partial HMs) and 896 (45%) as NPHMs (HMs not registered as PHMs). The average incidence of HM was 1.98/1000 deliveries. The incidence of PHM was 1.08/1000 deliveries and the incidence of NPHM was 0.90/1000 deliveries. Forty HMs were registered as second HMs; 85% (34/40) were of the same histopathological type as the first HM. The registered incidence of HM decreased from 2.55/1000 deliveries in 1999 to 1.61/1000 deliveries in 2014 (p < 0.005). The decrease in the incidence of HM was identical with a decrease in the incidence of PHM. New medical practices such as medical abortion and only forwarding selected pregnancy products for histopathologic examination may cause a declining number of HMs registered.

A review on management of gestational trophoblastic neoplasia

BACKGROUND

The rare presence of malignant cancerous cells afar any type of pregnancy is known as gestational trophoblastic neoplasia (GTN). GTN are benign lesions which mostly happen due to the activity of extravillous trophoblast cells and the placental villous tree development. These kinds of diseases would be occurring mainly due to the following clinicopathologic conditions: (I) existence of epithelioid trophoblastic tumor (ETT), (II) rare type of choriocarcinoma cancer, (III) gestational trophoblastic tumor of mole, and (IV) the rare malignant tumor of placental site trophoblastic tumor.

OBJECTIVE

This comprehensive study is trying to review the most recent approaches in comprehension of pathogenesis, more precise diagnosis, and also the most effective therapeutic procedures for patients who suffer from GTN disorders.

MATERIALS AND METHOD

A comprehensive research was carried out on scientific databases of Science Citation Index (SCI), MEDLINE, EMBASE, HMIC, PubMed, CINAHL, Google Scholar, Cochrane Database of Systematic Reviews (CDSR), and PsycINFO over the time period of 2005 to 2019. The keywords which applied for discovering more related records were including: Gestational trophoblastic diseases (GTD), Gestational trophoblastic neoplasia (GTN), molar pregnancy, choriocarcinoma, human chorionic gonadotropin (hCG), diagnosis, management and treatment.

CONCLUSION

In spite of the fact that GTN patients are treated with conventional surgical therapies or/and chemotherapy, in some patients with resistant disease, these therapies may not be effective and patients may die. Some novel remedial agents are required for decreasing the level of toxicity caused through administering conventional chemotherapy and also treating the patients who suffer from refractory or resistant disease. The newest issues are related to GTN diagnosis, process of progression of hydatidiform mole (HM) to GTN, and the issue of GTN drug resistance. In this regard, we should have a comprehensive knowledge on GTN genetics for answering all the available questions about this disorder.

Heuristic neural network approach in histological sections detection of hydatidiform mole

A heuristic-based, multineural network (MNN) image analysis as a solution to the problematical diagnosis of hydatidiform mole (HM) is presented. HM presents as tumors in placental cell structures, many of which exhibit premalignant phenotypes (choriocarcinoma and other conditions). HM is commonly found in women under age 17 or over 35 and can be partial HM or complete HM. Appropriate treatment is determined by correct categorization into PHM or CHM, a difficult task even for expert pathologists. Image analysis combined with pattern recognition techniques has been applied to the problem, based on 15 or 17 image features. The use of limited data for training and validation set was optimized using a k -fold validation technique allowing performance measurement of different MNN configurations. The MNN technique performed better than human experts at the categorization for both the 15- and 17-feature data, promising greater diagnostic consistency, and further improvements with the availability of larger datasets.

p57 in Hydatidiform Moles: Evaluation of Antibodies and Expression in Various Cell Types

Supplemental Digital Content is available in the text.

The protein p57 is encoded by CDKN1C. This gene is known to be paternally imprinted and maternally expressed in cytotrophoblasts and villous stromal cells. We present a method for evaluating p57 antibodies (Abs) in hydatidiform mole (HM) and demonstrate the results for 4 p57 Abs in various cell types. Five cases of complete HM, diploid with 2 paternal genome sets (CHM;PP), 5 cases of partial HM, triploid with 2 paternal and 1 maternal genome sets (PHM;PPM), and 5 cases of non-HM, with diploid biparental genomes (non-HM;PM) were stained with p57 Abs: 57P06, EP183, KP10, and KP39. Assessment of the fraction of nuclei stained, and the intensity of staining of the nuclei and cytoplasm was performed. For evaluation of the Abs, the observations in cytotrophoblasts, villous stromal cells, maternal decidual cells, and intermediate trophoblasts were scored. The fraction of stained nuclei in cytotrophoblasts and villous stromal cells and the staining of cytoplasm showed to be important parameters in the evaluation of the Abs. 57P06 was evaluated as optimal. KP10 showed moderate cytoplasmatic staining in maternal decidual cells and intermediate trophoblasts, and was evaluated as good. EP183 was evaluated as poor, primarily due to nuclear staining in ≥10% of the villous stromal cells in CHM;PP. KP39 was evaluated as poor, primarily due to strong cytoplasmatic staining in some cytotrophoblasts and villous stromal cells. A structured testing of p57 for diagnosing HM is recommended. No nuclear staining was observed in syncytiotrophoblasts of CHM;PP, indicating that in syncytiotrophoblasts also, CDKN1C is paternally imprinted.

Understanding and management of gestational trophoblastic disease

Gestational trophoblastic disease or neoplasia covers a spectrum of benign and malignant conditions arising from pregnancies with highly abnormal development of trophoblastic tissue. In this brief review, we discuss the different features of these different conditions and their origins and risk factors and introduce some of the more novel and controversial treatment options currently being explored.

Hydatidiform mole: validity of the registration in the Danish National Patient Registry, the Danish Cancer Registry, and the Danish Pathology Registry 1999-2009

Purpose

To examine the validity of registration of hydatidiform mole (HM) in the Danish National Patient Registry (NPR), the Danish Cancer Registry (DCR), and the Danish Pathology Registry (DPR).

Patients and methods

We selected women registered with a first-time HM code in NPR, DCR, and DPR from 1999 to 2009. We found most women registered in DPR. For a random sample of women registered in DPR, the coding was validated by comparing with the pathology report. Completeness and positive predictive value (PPV) of registration with an HM code in NPR and DCR were calculated using DPR as the reference. Details of women registered in NPR or DCR, but not in DPR, were scrutinized.

Results

In NPR and DPR, 1,520 women were identified in total; 1,057 (70%) were found in both registries, 65 (4%) only in NPR, and 398 (26%) only in DPR. In DCR and DPR, 1,498 women were identified in total; 1,174 (78%) in both registries, 47 (3%) only in DCR, and 277 (19%) only in DPR. For 149/150 randomly selected women registered with an HM code in DPR (99%), the pathology report was consistent with the diagnosis of HM. Completeness of NPR was 73% (95% CI: 70%–75%) and PPV was 94% (95% CI: 93%–95%). Completeness of DCR was 72% (95% CI: 69%–75%) in 1999–2003 and 90% (95% CI: 87%–92%) in 2004–2009. PPV of DCR was 96% (95% CI: 95%–97%) throughout the period.

Conclusion

Validation of registry data is important before using these. For research on the number of HMs in Denmark, DPR is the most valid data source. NPR and DCR appear to be equally valid before 2004. However, for research after 2004, DCR should be preferred rather than NPR.

Challenges in the Routine Praxis Diagnosis of Hydatidiform Mole: a Tertiary Health Center Experience

Introduction:

Hydatidiform moles (HM), presenting as complete (CHM) and partial (PHM) form, are rare pregnancy disorder. Diagnosis is based on clinical presentation, ultrasound imaging findings and pathological examination of products of conception. Protein p57, encoded by CKDN1C gene, is paternally imprinted and maternally expressed gene and provides quick insight in genetic basis of HM and allows distinction of CHM from all other conceptions. compare the preevacuational and pathohistological diagnosis with outcome of p57 immunostaining.

Material and methods:

All cases of HM diagnosed between January 2011 and December 2015 were included in this research. Maternal age, gestational age and input diagnosis data were recored. p57 immunostaining was performed in order to evaluate the diagnosis based on tissue slides examination.

Results:

There were 198 cases of histologically confirmed HM, 185 PHM, 12 CHM and one case of undefined HM. Mean maternal age in the CHM group was 24,7 and in the PHM group 26,9 years, with no significant differences among these two groups (p=0,27). For CHM mean gestational age was estimated at eight and for PHM 9,2 gestational weeks. Pregnant woman older than 40 years present significant earlier compared with younger woman (p<0,01), and those younger than 20 years tend to present at the beginning of the second trimester more often than older women (p<0,05). In the CHM group, 9 (75%) input diagnoses were mola in obs, and 3 (25%) of them were signed as abortion, unlike the PHM where 126 (67%) were qualified as abortion, 35 (19%) as blighted ovum, and 26 (14%) were suggestive for molar pregnancy. p57 immunostaining results confirmed all pathohistological diagnosis of CHM whereas 8% of PHM demonstrated divergent p57 expression.

Conclusion:

PHM, compared with CHM, represent a greater diagnostic challenge for both gynecologist and pathologist even when presenting in more advanced pregnancies.

Does hormonal contraception during molar pregnancy follow-up influence the risk and clinical aggressiveness of gestational trophoblastic neoplasia after controlling for risk factors?

OBJECTIVE

To evaluate the influence of hormonal contraception (HC) on the development and clinical aggressiveness of gestational trophoblastic neoplasia (GTN) and the time for normalization of human chorionic gonadotropin (hCG) levels.

METHODS

A retrospective cohort study was conducted with women diagnosed with molar pregnancy, followed at the Rio de Janeiro Trophoblastic Disease Center, between January 2005 and January 2015. The occurrence of postmolar GTN and the time for hCG normalization between users of HC or barrier methods (BM) during the postmolar follow-up or GTN treatment were evaluated.

RESULTS

Among 2828 patients included in this study, 2680 (95%) used HC and 148 (5%) used BM. The use of HC did not significantly influence the occurrence of GTN (ORa: 0.66, 95% CI: 0.24-1.12, p=0.060), despite different formulations: progesterone-only (ORa: 0.54, 95% CI: 0.29-1.01, p=0.060) or combined oral contraception (COC) (ORa: 0.50, 95% CI: 0.27-1.01, p=0.60) or with different dosages of ethinyl estradiol: 15mcg (ORa, 1.33, 95% CI 0.79-2.24, p=0.288), 20mcg (ORa: 1.02, 95% CI: 0.64-1.65, p=0.901), 30mcg (ORa: 1.17, 95% CI: 0.78-1.75, p=0.437) or 35mcg (ORa: 0.77, 95% CI: 0.42-1.39, p=0.386). Time to hCG normalization ≥10weeks (ORa: 0.58, 95% CI: 0.43-1.08, p=0.071) or time to remission with chemotherapy≥14weeks (ORa: 0.60, 95% CI: 0.43-1.09, p=0.067) did not significantly differ among HC users when compared to patients using BM, when controlling for other risk factors using multivariate logistic regression.

CONCLUSIONS

The use of HC during postmolar follow-up or GTN treatment does not seem to increase the risk of GTN or its severity and does not postpone the normalization of hCG levels.

Low molecular weight hyaluronan induces migration of human choriocarcinoma JEG-3 cells mediated by RHAMM as well as by PI3K and MAPK pathways

Hyaluronan (HA) is the major glycosaminoglycan present in the extracellular matrix. It is produced by some tumours and promotes proliferation, differentiation and migration among others cellular processes. Gestational trophoblastic disease (GTD) is composed by non-tumour entities, such as hydatidiform mole (HM), which is the most common type of GTD and also malignant entities such as choriocarcinoma (CC) and placental site trophoblastic tumour (PSTT), being CC the most aggressive tumour. Although there is a growing understanding of GTD biology, the role of HA in the pathogenesis of this group of diseases remains largely unknown. The aim of this work was to study the role of HA in the pathogenesis of GTD by defining the expression pattern of HA and its receptors CD44 and RHAMM, as well as to determine if HA can modulate proliferation, differentiation and migration of CC cells. Receptors and signalling pathways involved were also analyzed. We demonstrated that HA and RHAMM are differently expressed among GTD entities and even among trophoblast subtypes. We also showed that HA is able to enhance the expression of extravillous trophoblast markers and also to induce migration of JEG-3 cells, the latter mediated by RHAMM as well as PI3K and MAPK pathways. These findings indicate a novel regulatory mechanism for CC cell biology and also contribute to the understanding of GTD pathophysiology.

Abnormal villous morphology mimicking a hydatidiform mole associated with paternal trisomy of chromosomes 3,7,8 and unipaternal disomy of chromosome 11

Background

Pregnancies affected by non-molar chromosomal abnormality may sometimes demonstrate abnormal chorionic villous morphology that is similar to partial hydatidiform mole. Determination of the underlying aetiology may be difficult in such cases.

Case Presentation

This report describes a case referred to the regional trophoblastic disease unit as a possible hydatidiform mole that demonstrated both villous dysmorphology and abnormal p57^KIP2 expression. Molecular genotyping revealed that while most chromosomes in the villous tissue were diploid and biparental, chromosomes 3, 7 and 8 were trisomic with an additional paternally derived chromosome. In contrast chromosome 11 showed uniparental disomy of paternal origin a situation more usually associated with complete hydatidiform moles. This unusual case highlights that exceptions may occur to the general rules of both histological morphology and immunoprofile, and that these can be resolved by detailed molecular genetic investigations.

Conclusion

The findings confirm that trisomic pregnancies may demonstrate morphological villous features similar to hydatidiform mole, and that loss of p57^KIP2 expression occurs due to an absence of maternally transcribed genes on chromosome 11 and can therefore be independent of androgenetic complete hydatidiform mole.

Incidental Finding of Persistent Hydatidiform Mole in an Adolescent on Depo-Provera

Molar pregnancies represent an uncommon yet important obstetric problem with potentially fatal outcomes. Patients typically present with signs and symptoms of early pregnancy, and physicians most often suspect nonmolar pregnancy complications initially; however a hydatidiform mole should be included in the differential diagnosis of a woman with a positive pregnancy test and abnormal vaginal bleeding irrespective of the use of contraception. Our case is that of an adolescent female on Depo-Provera injectable contraceptive with increased vaginal bleeding, abdominal pain, nausea, and vomiting who was incidentally found to be pregnant and subsequently diagnosed with a molar pregnancy despite persistent denial of having initiated sexual intercourse. Though gestational trophoblastic disease is uncommon with an incidence of about 1-2 cases per 1,000 pregnancies, a clinician has to display a high index of suspicion when dealing with patients at extremes of age in order to avoid potentially life-threatening outcomes.

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%).

Paternal Hemizygosity in 11p15 in Mole-like Conceptuses: Two Case Reports

Hydatidiform mole is an abnormal human pregnancy characterized by the fetus being absent or nonviable, and the chorionic villi being vesicular and with trophoblastic hyperplasia. Most often, the mole phenotype is seen in conceptuses with an excess of paternally inherited genome set(s) relative to maternally inherited genome set(s), suggesting that the phenotype is caused by an excess of genome with a paternal imprinting pattern. However, it is unknown if correct parental origin of every imprinted gene is crucial for normal early differentiation or if abnormal parental imprinting of only one, or some, gene(s) can cause the mole phenotype.Two conceptuses included in the Danish Mole Project stood out since they presented with vesicular chorionic villi and without signs of fetal differentiation, and had apparently biparental diploid genomes, and no mutations in NLRP7 or KHDC3L were detected in the mothers. These conceptuses were subjected to a centralized histopathological revision and their genetic complements were scrutinized using fluorescence in situ hybridization, and DNA-marker and array comparative genomic hybridization analyses. Both conceptuses showed dysmorphic chorionic villi with some similarities to hydatidiform moles; however, no definite florid trophoblast hyperplasia was observed. Both conceptuses showed paternal hemizygosity of 11pter-11p15.4, most likely in nonmosaic state.Our findings suggest that the product of one (or a few) maternally expressed gene(s) on the tip of chromosome 11 is necessary for normal early embryonic differentiation. However, since the present two cases did not exhibit all features of hydatidiform moles, it is likely that abnormal parental imprinting of genes in other regions contribute to the phenotype of a hydatidiform mole.

Microscopic study of edema in hydatidiform mole

Objectives: the purpose of this study is to use light microscopy and scanning electron microscopy to determine the effect of edema on the structure of the molar vesicle. Methods: samples were taken from the complete hydatidiform mole and processed using conventional light and scanning electron microscopy techniques and an observation protocol that identified four variables: factors underlying the development of edema; the condition of the trophoblast basement membrane, development of the villi, accumulation and degeneration of sulphated mucosubstances at stromal level. Results: light microscopy showed a permeable trophoblastic basement membrane, a swollen syncytium, edematous regions disorganizating the stromal region and causing ischemic necrosis of cells. Using scanning electron microscopy, the basement membrane was found to be distended and thickened, with large irregular holes for the entry and movement of liquid, leaving a wide range of fluids during the influx process and depriving stromal cells of nutrition. Conclusions: a new three-dimensional view of the changes brought about by the entry of fluids into the stroma of molar hydropic vesicles was provided by scanning electron microscopy and confirmed by light microscopy, thereby explaining the changes occurring at the level of the stroma as an effect of the edema.

Clinical utility of selective molecular genotyping for diagnosis of partial hydatidiform mole; a retrospective study from a regional trophoblastic disease unit

AIMS

Hydatidiform moles (HMs) are genetically abnormal conceptions, associated with increased risk of gestational trophoblastic neoplasia. Diagnosis is usually based on histopathological criteria but in a minority definitive histological diagnosis is not possible; in such cases molecular genotyping may be diagnostic. This study describes the clinical usefulness of such an approach.

METHODS

Cases in which central histology review demonstrated abnormal villous morphological features insufficient for definite diagnosis of partial HM (PHM) ('favour PHM' or 'PHM not excluded') underwent molecular genotyping of villous and maternal tissue, using short tandem repeats, to determine ploidy and parental origin of the placental tissue.

RESULTS

Of 251 cases with non-diagnostic morphological villous abnormalities, molecular investigation was not possible in 14 (6%; limited material or technical issues). Overall, 124 (49%) were triploid including 71/86 (85%) of those morphologically favouring PHM, and 53/165 (32%) of those favouring non-molar miscarriage. Of 85 cases of triploidy in whom sufficient material was available, 84 had an additional paternal contribution. Single cases of digynic triploidy, tetraploid PHM and two mosaic conceptions were also identified. Twenty-three non-molar diploid cases (21%) exhibited trisomy.

CONCLUSIONS

Molecular genotyping allows definitive diagnosis of PHM for cases in which specialist histopathology review remains equivocal. While this approach provides definite diagnosis it is considerably more expensive than a pragmatic management approach of human chorionic gonadotrophin surveillance in all such cases.

Ectopic Complete Hydatidiform Mole Presenting as an Adnexal Tumor in a Postmenopausal Patient

Hydatidiform mole (HM) is rare in postmenopause, with only 7 cases reported. The occurrence of ectopic HM is also rare, with 26 fully documented tubal cases. We are not aware of any reported cases of ectopic HM in a postmenopausal patient. In a 51-year-old patient with 3 years amenorrhea, surgery revealed a necrotic, hemorrhagic mass involving the right peritubal space. Microscopically, chorionic villi were seen within the hemorrhagic mass accompanied by circumferential trophoblast hyperplasia. Immunohistochemically, p57(kip2) positive nuclei were prominent in the extravillous (intermediate) trophoblast. The HER2 FISH expression was diploid, consistent with the diagnosis of an early complete HM.

Placental Mesenchymal Dysplasia

Placental mesenchymal dysplasia is a rare, incompletely understood placental stromal lesion, characterized by placentomegaly and striking ectasia and tortuosity of chorionic plate and stem villous vessels. Its prenatal ultrasonographic and gross pathologic features resemble those of a partial mole, but the fetus is typically normal and the placenta has a diploid, chromosomal complement. We discuss the pathologic features and current understanding of the etiopathogenesis of this condition, the supportive immunohistochemical and confirmatory molecular genetic studies important in its diagnosis, and its implications for pregnancy and infant outcomes.

Diagnostic utility of microsatellite genotyping for molar pregnancy testing

CONTEXT

Molecular genotyping by analysis of DNA microsatellites, also known as short tandem repeats (STRs), is an established method for diagnosing and classifying hydatidiform mole. Distinction of both complete hydatidiform mole and partial hydatidiform mole from nonmolar specimens is relevant for clinical management owing to differences in risk for persistent gestational trophoblastic disease.

OBJECTIVE

To determine the technical performance of microsatellite genotyping by using a commercially available multiplex assay, and to describe the application of additional methods to confirm other genetic abnormalities detected by the genotyping assay.

DESIGN

Microsatellite genotyping data on 102 cases referred for molar pregnancy testing are presented. A separate panel of mini STR markers, flow cytometry, fluorescence in situ hybridization, and p57 immunohistochemistry were used to characterize cases with other incidental genetic abnormalities.

RESULTS

Forty-eight cases were classified as hydatidiform mole (31, complete hydatidiform mole; 17, partial hydatidiform mole). Genotyping also revealed 11 cases of suspected trisomy and 1 case of androgenetic/biparental mosaicism. Trisomy for selected chromosomes (13, 16, 18, and 21) was confirmed in all cases by using a panel of mini STR markers.

CONCLUSIONS

This series illustrates the utility of microsatellite genotyping as a stand-alone method for accurate classification of hydatidiform mole. Other genetic abnormalities may be detected by genotyping; confirmation of the suspected abnormality requires additional testing.

Management of a dichorionic twin pregnancy with a normal fetus and an androgenetic diploid complete hydatidiform mole

We describe a rare case of complete hydatidiform mole with twin live fetus (CHMTF) confirmed by histopathology, flow cytometry, and polymerase chain reaction techniques. No malformations were observed, fetal karyotype was normal and β-human chorionic gonadotropin levels were increased (>100,000 IU/ml). Once the patient had been informed of the risks, it was decided to continue the pregnancy, but termination of pregnancy was necessary at week 13 + 5 due to maternal complications consisting of hyperthyroidism, hypertension and vaginal bleeding, followed by persistent trophoblastic disease (PTD). Patients diagnosed with CHMTF should be informed of all known risks, including the considerable risk of PTD, which is similar to - or according to some reports - even higher than that associated with a singleton complete mole and is not increased by continuing pregnancy. Due to the low number of series published, evidence-based clinical management guidelines are lacking.

A major imprinted gene involved in hydatidiform mole is not located in 2q31.2-qter or 5q34-qter

INTRODUCTION

Hydatidiform mole is an abnormal human pregnancy, characterised by absent or abnormal embryonic differentiation, vesicular chorionic villi and trophoblastic hyperplasia. Although the mole phenotype has hereto not been correlated to mutations in the molar genome, the aetiology for hydatidiform moles clearly is genetic: Most molar genomes analysed either have had a relative excess of paternal genome sets relative to maternal genome sets, or a global error in maternally imprinted genes, giving them a "paternal pattern". However it remains yet to be specified which gene(s) in the molar genome actually causes the molar phenotype when present in a state of "paternal excess" or "maternal deficiency".

MATERIAL AND METHODS

A molar pregnancy in a woman with a balanced translocation (t(2;5) was subjected to histopathological evaluation and genetic analyses of ploidy and parental origin of the genome.

RESULTS

Morphology: Partial hydatidiform mole. Karyotyping of metaphase chromosomes: 69,XXY,der(5)t(2;5)(q23;q33)mat. SNP array analysis mapped the breakpoints to 2q31.2 (genome position 179Mb) and 5q34 (genome position 165Mb). DNA microsatellite marker analysis showed that for the regions not involved in the translocation, the conceptus had two paternal and one maternal allele(s). Telomeric to the breakpoint on chromosome 2, the mole had two paternal and two maternal alleles and telomeric to the breakpoint on chromosome 5 the mole had paternal alleles, exclusively.

CONCLUSIONS

If the molar phenotype is caused by paternal excess of one gene, only, it is unlikely that this gene is located telomeric to genome position 179Mb on chromosome 2. And similarly, if the phenotype complete mole is caused by the presence of exclusively paternally imprinted alleles of one gene, this gene is not located telomeric to genome position 165Mb on chromosome 5.