The histological diagnosis of hydatidiform moles

Diagnostic Utility of Twist1, Ki-67, and E-Cadherin in Diagnosing Molar Gestations and Hydropic Abortions

OBJECTIVES

This study aims to assess whether the expression of Twist1, Ki-67, and E-cadherin can guide the differential diagnosis of complete hydatidiform mole (CHM), partial hydatidiform mole (PHM), and hydropic abortion (HA).

METHODS

Differential expression of Twist1, Ki-67, and E-cadherin was analyzed in gestational products from 55 cases of CHM, PHM, and HA using immunohistochemistry. Prior to analysis, the studied cases were confirmed for their diagnosis by flow cytometric assessment of DNA ploidy and p57 immunostaining.

RESULTS

Twist1 expression can distinguish CHM from PHM and HA with 100% sensitivity, 100%, specificity, 100% positive predictive value (PPV), and 100% negative predictive value (NPV). Furthermore, combined Ki-67 and E-cadherin expression could differentiate PHM and HA with 100% sensitivity, 93.3% specificity, 92.3% PPV, and 100% NPV.

CONCLUSIONS

Twist1 expression is a highly reliable marker for the diagnosis of CHM, where combined Ki-67 and E-cadherin immunoreactivity can distinguish PHM from nonmolar pregnancies.

Predicting gestational trophoblastic neoplasia (GTN): is urine hCG the answer?

BACKGROUND

Previous studies on the significance of hCG to predict gestational trophoblastic neoplasia (GTN) have been too small for robust conclusions to be reached. Our aim in this study was to analyse the significance of urine hCG in predicting GTN in a large population.

METHODS

Details of 3926 patients were available for analysis. Information regarding age, dates of diagnosis and registration, urine hCG levels, antecedent pregnancy and chemotherapy were prospectively collected and used for analyses. Patients were stratified into different groups according to urine hCG level (IU/L); < 50, 50-99, 100-249, 250-499, 500-999, 1000-9999 and ≥10,000. Multivariate analyses were used to identify the prognostic indicators of GTN.

RESULTS

Urine hCG and antecedent pregnancy were the most powerful indicators for developing GTN (P<0.01). None of the patients with partial mole and urine hCG <50 IU/L (Normal level=40 IU/L) developed GTN. The risk of GTN was >35% in all patients with urine hCG ≥500 IU/L. GTN developed in 70% of patients with complete mole and urine hCG ≥10,000 IU/L.

CONCLUSION

Urine hCG is sensitive test for GTN. Urine hCG level is a powerful prognostic indicator for the GTN. Patients with partial mole could be safely discharged from the surveillance programme once their hCG have normalised. Patients with urine hCG ≥249 IU/L, whether partial or complete molar pregnancy, appear to benefit from intensive surveillance. Prophylactic chemotherapy could be considered when there are problems with surveillance.

Histopathological diagnosis of hydatidiform mole: contemporary features and clinical implications

Gestational trophoblastic neoplasia (GTN) encompasses several entities including complete (CHM) and partial (PHM) hydatidiform mole (HM), malignant choriocarcinoma, and placental-site trophoblastic tumor. HMs are genetically abnormal, nonviable conceptions, which are associated with significantly increased risk for development of complications due to persistence of abnormal trophoblast (persistent GTN; pGTN), which occurs following 15% of CHM and 0.5% of PHM. Diagnostic histological features of HM are present in the first trimester but these features differ from those traditionally described in the later second trimester. The characteristic morphological findings of early HM include aspects of villous dysmorphism and abnormal villous trophoblast hyperplasia, with other specific features allowing reliable distinction between CHM and PHM. Optimal management of molar disease depends on its early histological identification and subsequent surveillance by measurement of maternal human chorionic gonoadotropin (hCG) for detection of pGTN based on rising or plateuing hCG levels such that early effective treatment is possible.

[Maze-like vascular anomaly in partial mole. Interest for the pathological diagnosis of partial mole on chorionic villous sampling]

A case of maze-like angiomatoid anomaly in villi obtained by chorionic villous sampling (CVS) is described. This feature is pathognomonic of partial mole (triploid syndrome) and it was later confirmed by chromosomal analysis. Maze-like angiomatoid anomaly was previously described on specimen submitted after spontaneous or induced abortions, but it was never reported on CVS. This report emphasized that microscopic investigation of CVS cannot be conclusive for cytogenetic anomaly in almost all cases excepted for partial mole where diagnosis criteria are usually characteristic.

False-positive beta-human chorionic gonadotropin values in the follow-up of gestational trophoblastic disease

Gestational trophoblastic disease consists of a pathological spectrum of entities from molar pregnancies, which are premalignant conditions, to malignant invasive choriocarcinoma. Serum Beta-human chorionic gonadotropin (hCG) levels are essential both in the diagnosis and in the follow-up. There are high rates of complete responses and long-term survivors, because of the excellent chemosensitivity of these tumours. After initial management, an increased level of Beta-hCG indicates persistent disease. However, in the absence of evidence of persistent disease, false-positive Beta-hCG values may be considered. We present here the case of a woman with a metastatic choriocarcinoma in complete response after chemotherapy, who developed later persistent false-positive values of Beta-hCG in the follow-up. Causes of false-positive Beta-hCG determinations are revised.

Clinicopathologic characteristics and subsequent pregnancy outcome in 139 complete hydatidiform moles

OBJECTIVE

The most common form of gestational trophoblastic disease is the complete hydatidiform mole (CHM). The study reports our experience of clinicopathologic characteristics and subsequent pregnancy outcome of patients with CHM.

STUDY DESIGN

One hundred fifty-one subsequent cases with initial diagnosis of CHM were re-evaluated histopathologically. Clinical characteristics, the need for chemotherapy and subsequent pregnancy outcome were evaluated.

RESULTS

Twelve out of 151 cases were re-evaluated as hydropic abortion, as partial hydatidiform moles or were insufficient for morphologic examination and therefore excluded from further analysis. The leading clinical symptoms of the remaining 139 cases were irregular vaginal bleeding (67%) and uterine enlargement (41%). Twenty-six patients (19%) required chemotherapy because of gestational trophoblastic neoplasia (GTN; low-risk: 23 out of 26). All patients were cured successfully. The subsequent pregnancy rate was 15% (21/139). Five patients suffered from abortions, 12 women delivered a healthy offspring. Four women presented with recurrent CHM with a spontaneous normalization of HCG levels after D&C.

CONCLUSIONS

The clinical and morphologic diagnosis of CHM is a challenge, and diagnosis as well as treatment should be multidisciplinary and centralised. One fifth of CHM are at risk of a GTN, but the cure rate is 100% with adequate management. Pregnancy outcome following CHM is complicated by an increased risk of abortion.

Prognostic value of trophoblastic proliferation in complete hydatidiform moles in predicting persistent disease

The clinical outcome of patients with complete hydatidiform moles (CHM) is variable. The correlation between trophoblastic proliferation and development of persistent disease was evaluated. A hundred and fifty-one cases with the initial diagnosis of CHM were re-evaluated histopathologically. The need for chemotherapy and occurrence of metastatic disease was correlated with the histologic grade using a three-level score. Twelve out of 151 cases were re-evaluated as hydropic abortion, partial moles, or were insufficient for morphologic examination, representing a diagnostic agreement of 92%. A total of 63.4% of the CHM presented with low trophoblastic proliferation with focal areas of slight hyperplasia (grade 1), and 23.7% with moderate proliferation with slight anaplasia and medium-sized sheets of free trophoblast in between the villies (grade 2). In all, 12.9% of the cases showed marked hyperplasia with marked anaplasia and involvement of nearly all villies, as well as a large amount of intervillous trophoblastic sheets (grade 3). Twenty-six of the CHM (19%) required chemotherapy. Grade 3, on histology, showed a positive correlation with the necessity of chemotherapy (p=0.04), but not with the occurrence of metastatic disease. Histomorphology might predict the risk of persistent disease, indicating the necessity for closer a follow-up, but further studies are required.

Routine pre-evacuation ultrasound diagnosis of hydatidiform mole: experience of more than 1000 cases from a regional referral center

OBJECTIVES

To examine the accuracy of sonographic findings of routine ultrasound examinations in patients with a proven histological diagnosis of complete or partial hydatidiform mole referred to a supra-regional referral center, and to examine the relationship of sonographic findings to gestational age across the first and early second trimesters.

METHODS

Review of consecutive cases referred to a trophoblastic disease unit from June 2002 to January 2005 with a diagnosis of possible or probable hydatidiform mole in whom results of a pre-evacuation ultrasound examination were documented. Ultrasound detection rates for partial and complete hydatidiform moles were calculated and comparison of detection rates between complete and partial mole, and gestational age groups carried out.

RESULTS

1053 consecutive cases were examined. The median maternal age was 31 (range, 15-54) years and the median gestational age was 10 (range, 5-27) weeks. 859 had a final review diagnosis of partial or complete hydatidiform mole (82%), including 253 (29%) complete moles and 606 (71%) partial moles. Non-molar hydropic miscarriage was diagnosed following histological review in 194 (18%). Overall, 378 (44%) cases with a final diagnosis of complete or partial hydatidiform mole had a pre-evacuation ultrasound diagnosis suggesting hydatidiform mole, including 200 complete moles and 178 partial moles, representing 79% and 29%, respectively, of those with complete (253) or partial (606) moles in the final review diagnosis. The ultrasound detection rate was significantly better for complete versus partial hydatidiform moles (Z = 13.4, P < 0.001). There was a non-significant trend towards improved ultrasound detection rate with increasing gestational age, with an overall detection rate of 35-40% before 14 weeks' gestation compared to around 60% after this gestation. The sensitivity, specificity, positive predictive value and negative predictive value for routine pre-evacuation ultrasound examination for detection of hydatidiform mole of any type were 44%, 74%, 88% and 23%, respectively.

CONCLUSIONS

Routine pre-evacuation ultrasound examination identifies less than 50% of hydatidiform moles, the majority sonographically appearing as missed or incomplete miscarriage. Detection rates are, however, higher for complete compared to partial moles, and improve after 14 weeks' gestation. Histopathological examination of products of conception remains the current gold standard for the identification of gestational trophoblastic neoplasia.

Routine histopathologic analysis of product of conception following first-trimester spontaneous miscarriages

AIM

To evaluate the histopathologic findings relating to tissue samples collected at surgical uterine evacuation in first-trimester spontaneous miscarriages.

METHODS

In this retrospective study, histopathologic diagnosis of the tissue samples obtained via surgical uterine evacuation in patients who were admitted to the Early Pregnancy Clinic in a 12-month period with the diagnosis of incomplete miscarriage (n = 970), missed miscarriage (n = 406) and anembryonic miscarriage (n = 230) in the first trimester was recorded and compared with the presurgery diagnosis.

RESULTS

Uterine evacuation was performed in cases of incomplete miscarriage (n = 970, 60.4%), missed miscarriage (n = 406, 25.2%) and anembryonic miscarriage (n = 230, 14.3%). Histopathologic examination revealed the product of conception in 1119 patients (69.7%), while partial hydatidiform mole was diagnosed in 33 patients (2.1%). Complete hydatidiform mole was detected in only seven cases (0.43%). Exaggerated placental site and placental site trophoblastic nodule was detected in two cases (0.12%). Decidual tissue without chorionic villi was reported in 272 patients (16.9%), raising the suspicion of presence of other pathology.

CONCLUSIONS

By routine histopathologic assessment of products of first-trimester spontaneous miscarriages, important pathologies such as molar pregnancy and placental trophoblastic disease can be diagnosed. Histopathological assessment has great value in the identification of an ectopic pregnancy or infection when compared with clinical and laboratory findings.

A prospective study of ultrasound screening for molar pregnancies in missed miscarriages

OBJECTIVE

To examine the relationship between ultrasound and histological features in the screening for molar changes in missed miscarriage.

METHODS

A prospective cohort study was conducted on all missed miscarriages, with features suspicious of molar pregnancy, on transvaginal ultrasound and/or on histological examination over a 5-year period. All cases of molar pregnancy diagnosed histologically were examined and cross-referenced with cases diagnosed on ultrasound and with the supplementary report from the regional referral center. When available, maternal serum beta-human chorionic gonadotropin (hCG) levels were recorded.

RESULTS

Fifty-one cases of suspected molar pregnancy were referred to the regional center for further histological opinion and follow-up, and five cases were subsequently excluded from the final analysis because of the diagnosis of hydropic abortion (HA). In 33 cases a molar pregnancy was suspected at the initial scan. Of these, 26 (78.8%) were confirmed on histology, resulting in a 56% detection rate using ultrasound alone. In 15 cases hCG results were available, of which nine were greater than two multiples of the median.

CONCLUSIONS

The diagnosis of both complete (CHM) and partial (PHM) hydatidiform moles in first-trimester miscarriages is difficult. hCG is significantly higher in both CHM and PHM and, in conjunction with transvaginal ultrasound, could provide the screening test required to enable clinicians to counsel women more confidently towards non-surgical methods of management of their miscarriage, where histopathological examination is not available.

Gestational trophoblastic disease: is intensive follow up essential in all women?

OBJECTIVE

To determine the timescale of the registration process for gestational trophoblastic disease and its impact on hCG level at registration and subsequent need for chemotherapy.

DESIGN

A prospective observational study using a standardised protocol for registration, assessment and treatment for molar pregnancy.

SETTING

A supra-regional tertiary referral centre for gestational trophoblastic disease.

PARTICIPANTS

A total of 2046 consecutive women registered between January 1994 and December 1998 with a diagnosis of molar pregnancy.

METHODS

Data at and after registration, collected prospectively on a computerised database, were statistically analysed (by multiple logistic regression and ANOVA).

MAIN OUTCOME MEASURES

Relationship between length of time to and hCG value at registration; also the subsequent need for chemotherapy.

RESULTS

A total of 2046 women with a diagnosis of molar pregnancy were registered in the study period. The mean time interval between first evacuation and registration at the referral centre was 47 days (median 37, range 0-594). One hundred and five out of 2046 (5.1%) women needed chemotherapy. Sixty-three precent of the women (1296 out of 2046) had a normal level of urinary hCG (less than 40 IU/24 hours) at the time of registration and only one (0.08%) needed chemotherapy. Binary logistic regression analysis showed a statistically significant relationship between time to registration, hCG value, histology, pretreatment risk score and decision to administer chemotherapy.

CONCLUSION

Women with gestational trophoblastic disease who were registered late were significantly more likely to have normal levels of hCG and were less likely to need chemotherapy. A less intensive follow up may be justified in women with gestational trophoblastic disease who are registered with a normal hCG level.

Genomic imprinting in gestational trophoblastic disease--a review

The abnormal pregnancy hydatidiform mole (HM) can be classified as complete (CHM) or partial (PHM) on the basis of both morphology and genetic origin. PHM are diandric triploids while almost all CHM are androgenetic. Thus the characteristic trophoblastic hyperplasia seen in both CHM and PHM is usually associated with the presence of two paternal genomes. Very occasionally CHM may be diploid, but biparental, in origin. These rare BiCHM are found in patients with recurrent HM and appear to be associated with an autosomal recessive condition predisposing to molar pregnancies. Since they are pathologically indistinguishable from androgenetic CHM, BiCHM are also likely to result from defects in genomic imprinting. There is evidence that the gene mutated in this condition, provisionally mapped to 19q13.3-13.4, may be important in setting the maternal imprint in the ovum. Women with BiCHM have a much higher risk of recurrent HM than women with AnCHM and an appreciable risk of persistent trophoblastic disease. Investigation of these unusual BiCHM and isolation of the defective gene will lead to a greater understanding of the function of genomic imprinting in early development.

Histopathological diagnosis of partial and complete hydatidiform mole in the first trimester of pregnancy

The diagnosis of molar pregnancy is a continuing diagnostic problem for many practicing histopathologists who are required to examine specimens of products of conception, particularly since changes in gynecological management in recent years have resulted in uterine evacuation at earlier gestations. The aim of this review is to provide practical, up-to-date, diagnostically useful information regarding the histological diagnosis of molar disease in early pregnancy. Pathophysiological issues relevant to molar pregnancies, such as genetic abnormalities, will be briefly summarized, but nonhistopathological aspects of molar disease will not be covered in detail in this review.

Histological analysis of the products of conception following first trimester abortion at Jordan University Hospital

OBJECTIVE

To evaluate the value of histopathological examination of products of conception in first trimester abortion.

SETTINGS

University hospital.

DESIGN

Retrospective record review over 2 years, from January 1999 to January 2001.

PATIENTS

A total number of 293 patients with the diagnosis of first trimester abortion were admitted and their abnormal pregnancy evacuated.

RESULTS

The highest type of abortion among the studied group was incomplete abortion, 140 patients (48%), and surgical evacuation was the most common method of termination, 202 patients (69%). The histopathology reports confirmed the pregnancy in all patients and revealed partial mole in 51 patients (17%), undiagnosed abnormality in 8 patients (2.7%), suggesting the possible cause for recurrent pregnancy loss in 4 patients (1.4%).

CONCLUSION

Histopathological assessment for the products of conception proved to be an important tool in detecting molar pregnancy and hydropic changes that necessitate special follow-up protocol and unmasking ectopic pregnancies for further management.

Role of hysterectomy in management of gestational trophoblastic disease

OBJECTIVE

To evaluate incidence, indications, and outcome of hysterectomy in women presenting with gestational trophoblastic disease.

METHODS

A prospective observational study using a standardized protocol for registration, assessment, and treatment of gestational trophoblastic disease. A total of 5976 consecutive new patients registered between January 1986 and December 2000 with a diagnosis of gestational trophoblastic disease. The setting was a supraregional tertiary referral center for gestational trophoblastic disease.

RESULTS

Between January 1 1986 and December 31 2000, 5976 new patients with a diagnosis of gestational trophoblastic disease were registered at Weston Park Hospital, Sheffield. Of these patients, 301 required chemotherapy. Forty patients underwent hysterectomy. The average pretreatment risk score in women who had hysterectomy was 7.4. The mean time interval between diagnosis of molar disease and hysterectomy was 17 months. Indications for hysterectomy included uncontrollable vaginal or intraabdominal bleeding, localized chemo-resistant disease, and placental site trophoblastic tumor. In this group, 31 of 40 women had chemotherapy and 14 patients needed more than one regimen. These women were also more likely to have atypical histology (3 invasive moles, 6 placental site trophoblastic tumours, 13 choriocarcinomas, and 2 dimorphic tumours). There were 10 deaths in all registered patients with molar disease and 4 of these were in the hysterectomy group.

CONCLUSION

Hysterectomy was performed in 1 in 150 northern UK women with gestational trophoblastic disease. Patients needing hysterectomy represent an increased-risk group as indicated by their high pretreatment risk scores, atypical histology, frequent use of salvage chemotherapy, and higher mortality.

Outcome of twin pregnancies with complete hydatidiform mole and healthy co-twin

We assessed 77 twin pregnancies, comprising complete hydatidiform mole (CHM) and healthy co-twin, to ascertain the risks to the mother and baby of continuing the pregnancy, versus termination. 24 women with histologically confirmed CHM and healthy co-twin pregnancies decided to have a termination. 53 women continued with their pregnancies, though two had to have terminations because of severe pre-eclampsia, and 23 spontaneously aborted (<24 weeks' gestation). 28 pregnancies lasted 24 weeks or more, resulting in 20 livebirths. Chemotherapy to eliminate persistent gestational trophoblastic disease (pGTD) was required in three of 19 women (16%; 95% CI 3-39) who terminated their pregnancies in the first trimester, and in 12 of 58 (21%; 95% CI 11-33%) who continued their pregnancies. CHM and healthy co-twin pregnancies have a high risk of spontaneous abortion, but about 40% result in livebirths, without significantly increasing the risk of pGTD.

Risk of partial and complete hydatidiform molar pregnancy in relation to maternal age

All cases of first histologically confirmed complete and partial moles registered between 1985 and 1999 were identified from the database of a Trophoblastic Disease Registration Centre. The maternal age distribution at diagnosis was calculated for the 7916 molar pregnancies and compared with the maternal age distribution of an unselected population of women from a routine obstetric database. Likelihood ratios were calculated for complete and partial molar pregnancies by maternal age. A positive relationship was found between the risk of molar pregnancy and both upper and lower extremes of maternal age (> or = 45 years and < or = 15 years, respectively). This association, although present for both complete and partial moles, is much greater for complete mole at all maternal ages, and the degree of risk is much greater with older (> or = 45 years) rather than younger (< or = 15 years) maternal age. This study provides, for the first time, data regarding specific risk of partial versus complete hydatidiform mole with maternal age.

The diagnostic implications of routine ultrasound examination in histologically confirmed early molar pregnancies

OBJECTIVE

Early ultrasound examination is being used increasingly in the diagnosis of molar pregnancy. The aim of this study was to examine the diagnostic implications of routine ultrasound examination for histologically confirmed molar pregnancies.

METHODS

This was a retrospective review of sonographic and histological findings in a series of consecutive cases referred to the National Trophoblastic Disease Surveillance Centre with suspected molar pregnancies. In 194 cases referred to the center over a 6-month period in whom results of a preceding ultrasound examination were documented, review of ultrasound findings and final histological diagnosis was carried out.

RESULTS

There were 155 cases with a reviewed histological diagnosis of complete or partial hydatidiform mole. In 131 (67%) cases, the sonographic diagnosis was that of a missed miscarriage/anembryonic pregnancy with no documented suspicion of molar pregnancy, referral being on the basis of histological examination of products of conception. In 63 cases, ultrasound examination suggested molar pregnancy; in 53 (84%) of these, the diagnosis of molar pregnancy was correct. Overall, 37 of 64 (58%) complete moles had sonographic evidence of molar pregnancy compared to 16 of 91 (17%) partial moles. Of 155 histologically confirmed complete or partial hydatidiform moles, only 53 (34%) were suspected as molar sonographically.

CONCLUSION

The majority of cases of molar pregnancy now present as missed miscarriage/anembryonic pregnancy sonographically, highlighting the importance of histological examination to diagnose gestational trophoblastic disease.

Pseudo-partial moles: placental stem vessel hydrops and the association with Beckwith-Wiedemann syndrome and complete moles

AIMS

To describe the clinical and histological features of a series of cases of placentas originally diagnosed as partial moles in which the final diagnosis was that of placental stem villous hydrops, mesenchymal dysplasia or Beckwith-Wiedemann syndrome.

METHODS AND RESULTS

We searched a computerized database containing cases of suspected or proven trophoblastic disease examined at the Trophoblastic Disease Unit at Charing Cross Hospital, London, to identify cases in which stem vessel hydrops was present without other histological features of partial mole. For each case, histological sections were examined and the histological features present recorded. There were 15 cases identified. Placental weight was above the 95th centile of the normal for gestation in all cases in which this information was documented. In an additional five cases the placenta was described as 'large'. All cases had marked stem vessel hydropic change with cyst formation and in the majority of cases some terminal villous hydrops was also present. In 13 of the 15 cases there was marked aneurysmal dilatation of stem villous vessels. Nine had focal chorioangiomatoid change and in four of these extramedullary haematopoiesis was focally present in these areas. No excessive trophoblast proliferation was noted in any case and no trophoblastic inclusions typical of partial mole were identified.

CONCLUSIONS

This study has identified cases of stem villous hydrops, mesenchymal dysplasia or Beckwith-Wiedemann spectrum in pregnancies initially diagnosed as partial hydatidiform mole in the second half of pregnancy and has highlighted the need for detailed pathological examination and clinicopathological correlation in all such cases.

Should tissue from pregnancy termination and uterine evacuation routinely be examined histologically?

OBJECTIVE

To assess the value of routine histological examination of tissue samples collected at termination of pregnancy in the first trimester and emergency surgical uterine evacuation.

SETTING

The gynaecological department of a teaching hospital.

DESIGN

Prospective study of women attending the gynaecological department in a 12-month period.

PARTICIPANTS

All women undergoing a therapeutic first trimester medical or surgical abortion or an emergency surgical evacuation of a failed pregnancy, suspected incomplete spontaneous miscarriage or incomplete induced abortion.

MAIN OUTCOME

Association of pre-operative clinical diagnosis and the post-operative histological result.

RESULTS

Of 1,576 women studied, the histological report confirmed that products of conception were obtained in 1,465 (93%); in two women (0.13%) molar changes were reported confirming the preoperative diagnosis by ultrasound. Products of conception were not confirmed in the tissue specimens in 0.5% medical terminations, 5% surgical terminations, 10% evacuations following a previous evacuation, 12% evacuations for a failed pregnancy, and 19% evacuations for an incomplete miscarriage. In 87 women (6%), decidua was reported; two of these women had undergone an evacuation for an ultrasound diagnosis of spontaneous miscarriage, but in both a tubal ectopic pregnancy was subsequently diagnosed.

CONCLUSION

There did not appear to be any obvious benefit from routine histological examination of tissue removed at termination of pregnancy or emergency uterine evacuation. The histological result was sometimes not consistent with the pre-operative diagnosis and may result in unnecessary further investigation and treatment unless due consideration is given to the clinical presentation.

Amniotic tissue in complete hydatidiform moles can be androgenetic

The purpose of this study was to determine whether amniotic tissue found associated with cases of complete hydatidiform mole (CM) was genetically identical to the CM, and therefore part of the molar pregnancy, or genetically dissimilar to the CM, suggesting derivation from a twin pregnancy. DNA was prepared from formalin-fixed, paraffin-embedded blocks of tissue containing both CM and amnion. Maternal DNA was prepared from decidual tissue in the same blocks, or from a maternal blood sample. Fluorescent microsatellite genotyping was carried out to determine the origin of both the CM and the amniotic tissue. In one of six cases examined, the amniotic tissue was genetically different from the CM and was therefore likely to be derived from a twin pregnancy. In the five remaining cases, the amniotic tissue was genetically identical to the CM and was likely to be derived from the same conceptus. It is concluded that androgenetic CM can support the development of amniotic tissue and that some early embryonic development may occur in CM. The presence of amnion, or other fetal tissues, associated with molar tissue should not therefore always be considered indicative of a diagnosis of partial mole (PM).

Repetitive complete hydatidiform mole can be biparental in origin and either male or female

Complete hydatidiform mole (CHM) is an abnormality in pregnancy due to a diploid conception which is generally androgenetic in origin, i. e. all 46 chromosomes are paternally derived. We have examined the genetic origin of repetitive hydatidiform moles in a patient having three CHM by two different partners, and no normal pregnancies. Using fluorescent microsatellite genotyping, we have shown all three CHM to be biparental, rather than androgenetic, in origin. Examination of informative markers for each homologous pair of chromosomes, in two of the CHM, failed to reveal any evidence of unipaternal disomy, suggesting that the molar phenotype might result from disruption of normal imprinting patterns due to a defect in the maternal genome. It has been suggested that intracytoplasmic sperm injection (ICSI), followed by selection of male embryos, can prevent repetitive CHM; but examination of sex chromosome-specific sequences in the three CHM described here, showed that, while two were female, the first CHM was male. Selection of male embryos is therefore unlikely to prevent repetitive CHM in this patient. Our results suggest that the genetic origin of repetitive CHM should be determined prior to in-vitro fertilization (IVF) and that current strategies for the prevention of repetitive CHM may not be appropriate where the CHM are of biparental origin.

Triplet pregnancy with hydatidiform mole

Multiple pregnancies with hydatidiform mole are rare. We describe here a patient who delivered a male fetus and a female fetus together with molar tissue following treatment for infertility. comparing microsatellite polymorphisms in the DNA from the patient, her partner, the two normal placentas and the molar tissue, we were able to show that this was a triplet pregnancy with two normal conceptions and a complete hydatidiform mole of monospermic origin.

Recent advances in gestational trophoblastic disease

Advances in the last 20 years have led to a better understanding of the process of gestational trophoblastic disease (GTD), and consequently, to improved diagnosis, management, and prognosis. Patients with GTD should be registered at a trophoblastic disease center for follow-up, and those with persistent disease should receive chemotherapy, methotrexate, and folinic acid for low-risk disease, and EMACO (etoposide, actinomycin-D, methotrexate, vincristine, and cyclophosphamide) for high-risk disease, without loss of fertility. Most patients with relapsing or resistant disease can be treated effectively with surgery and/or cisplatin in EP/EMA (etoposide, platinum-etoposide, methotrexate, actinomycin-D) combination.

Early complete hydatidiform moles contain inner cell mass derivatives

In four cases of early complete hydatidiform moles, confirmed to be androgenetic in origin by DNA studies, we have identified nonchorionic inner cell mass derived structures which are not commonly observed in specimens of later gestational age. These structures include nucleated red blood cells, endothelial cells, stromal macrophages, amnion and yolk sac. The latter four structures were confirmed by specific immunocytochemical stains. Recognition that such structures can accompany complete hydatidiform moles has both theoretical and practical significance. From a theoretical perspective, it demonstrates that the maternal genome is not required for the initiation of amniogenesis, development of the yolk sac, vasculogenesis, or hematopoiesis. From a practical perspective it emphasizes that complete hydatidiform moles, with their markedly increased risk of subsequent choriocarcinoma, cannot be excluded based on the finding of "fetal structures."

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.