Hydatidiform mole in southern Iran: a statistical survey of 113 cases

Gestational Trophoblastic Disease at Sultan Qaboos University Hospital: Prevalence, Risk Factors, Histological Features, Sonographic Findings, and Outcomes

Objectives

We sought to assess the prevalence of gestational trophoblastic diseases (GTD) among pregnant women at Sultan Qaboos University Hospital (SQUH) and compare our results with the international studies. We also sought to determine the risk factors, histological features, sonographic findings, and outcomes in women with GTD.

Methods

We conducted a retrospective cohort study of all women diagnosed with GTD and followed at SQUH between November 2007 and October 2015. We collected data on maternal demographics, risk factors, sonographic features, histological diagnosis, follow-up period, and chemotherapy treatment from the hospital information system.

Results

Sixty-four women with GTD were included in the study with a mean age of 31.0±7.5 years, mean gravidity 4.0, and parity 2.0. The prevalence of GTD was 0.3% (one in 386 births), and the most common risk factors were increased maternal age and multiparity. A partial hydatidiform mole was diagnosed in 54.7%, complete hydatidiform mole in 43.8%, and invasive mole in 1.6% of women. Eleven percent of women required chemotherapy. Typical ultrasound features for partial molar pregnancy were present in 54.7% of our sample, while snowstorm appearance was seen in 89.3% of those with complete mole. Negative beta-human chorionic gonadotropin was achieved 70 days after diagnosis in 41 women.

Conclusions

The awareness of the risks and complications of GTD among physicians with close follow-up is paramount. There is a need to establish a national registry of GTD cases in Oman.

Recognising gestational trophoblastic disease

Gestational trophoblastic disease (GTD) is a group of interrelated tumours originating from the placenta. Hydatidiform molar (HM) pregnancy is the most common form of GTD; this includes both partial hydatidiform molar (PHM) and complete hydatidiform molar (CHM) pregnancies. The importance of such a condition derives from its potential for persistent trophoblastic disease; this is noted to be more common after a CHM (10-20%) compared to a PHM (0.1-11%). The recent routine use of high-resolution trans-vaginal ultrasound (TVS) in early pregnancy has improved the recognition and thus pre-surgical diagnosis of molar pregnancy. Pre-surgical recognition aids planning of surgery, decreases intra-operative complications and identifies women with potential persistent trophoblastic disease. Despite the introduction of TVS, its performance in preoperative diagnosis is quite poor. This is primarily because of the histomorphometric features of the hydropic villi. A significant proportion of HM cases demonstrates minimal hydropic change in the first trimester and therefore is likely to remain unidentifiable by ultrasound examination prior to surgical evacuation, even with improved sonographer expertise. The overall sensitivity for the ultrasound diagnosis of HM is 50-86%. Ultrasound diagnosis of CHM can be made in approximately 80% of the cases, whilst ultrasound diagnosis of PHM is less accurate and nearly 70% of cases will be missed. Correlation of the ultrasonographic findings with human chorionic gonadotropin levels can further improve the recognition of HM pregnancy pre-surgery. Although ultrasound can be helpful in the diagnosis of molar pregnancies, histological confirmation is mandatory. Histological confirmation post-curettage is still the gold standard for the diagnosis of GTD. In this article, we critically evaluate the role of TVS in the pre-surgical recognition of GTD.

The genetics of hydatidiform moles: new lights on an ancient disease

Hydatidiform mole (HM) is a human pregnancy with no embryo but cystic degeneration of chorionic villi. The common form of this condition occurs in 1 in every 1500 pregnancies in western societies and at a higher incidence in some geographic regions and populations. Recurrent moles account for 2% of all molar cases and a few of them occur in more than one family member. By studying a familial form of recurrent moles, a recessive maternal locus responsible for this condition was mapped to 19q13.4 and causative mutations identified. The defective protein, NALP7, is part of the CATERPILLAR protein family with roles in pathogen-induced inflammation and apoptosis. The exact role of NALP7 in the pathophysiology of molar pregnancies is unknown yet. NALP7 could have a role either in oogenesis or in the endometrium during trophoblast invasion and decidualization. In this review, we outlined recent advances in the field of HMs and reviewed the literature in the light of the new data.

Epidemiology and aetiology of gestational trophoblastic diseases

Gestational trophoblastic diseases (GTD) consist of a group of neoplastic disorders arising from placental trophoblastic tissue after normal or abnormal fertilisation. The WHO classification of GTD includes hydatidiform mole, invasive mole, choriocarcinoma, placental site trophoblastic tumour, and miscellaneous and unclassified trophoblastic lesions. GTD have a varying potential for local invasion and metastases and they generally respond to chemotherapy. Broad variations in the distribution of GTD exist worldwide, with higher frequencies in some parts of Asia, the Middle East and Africa, but the extent to which they can be attributed to methodological difficulties in obtaining accurate rates is unclear. Maternal age and a history of GTD have been established as strong risk factors for hydatidiform mole and choriocarcinoma. We review published data on the worldwide distribution of GTD, original data from cancer- registry-based statistics on choriocarcinoma, and major aetiological hypotheses, including parental age, AB0 blood groups, history of GTD, reproductive factors, oral contraceptive use, and other environmental factors.

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.

Gestational trophoblastic tumors

Although virtually 100% of women who develop gestational trophoblastic tumors enter a long-term complete remission, there are many aspects of trophoblastic disease that arouse interest. Epidemiological studies have shown a large geographical variation in the percentage of conceptions that result in a hydatidiform mole and have stimulated studies on the immunological differences of the low and high risk populations. Chromosomal analysis is now complementing the pathological differentiation between complete and partial moles. There is still debate as to which factors are positively associated with the progression of a hydatidiform mole through invasive mole to choriocarcinoma. There are also considerable differences in the proportion of molar patients receiving chemotherapy in different centers. In addition to these topics, this article will review several recently introduced treatment regimens which show improved results with reduced toxicity.

Epidemiology of gestational trophoblastic disease

The epidemiology of gestational trophoblastic disease is not well understood. Methodologic problems with published reports limit the interpretation of incidence data, although the frequency of hydatidiform mole appears to be about one per 1000 pregnancies. No consistent temporal trends in rates of either hydatidiform mole or choriocarcinoma are evident. Hydatidiform mole appears to be caused by abnormal gametogenesis and fertilization. Age, ethnicity, and a history of hydatidiform mole appear to be important risk factors for hydatidiform mole. Age, ethnicity, a history of hydatidiform mole or fetal wastage, and ABO blood group interactions appear to be important risk factors for choriocarcinoma. Future studies should focus on the mechanisms by which these risk factors influence gametogenesis, fertilization, and malignant transformation of trophoblastic tissue.

Epidemiology of gestational trophoblastic neoplasm at the Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia

This retrospective research was conducted in the Department of Obstetrics and Gynaecology of the Dr. Cipto Mangunkusumo Hospital, Jakarta, covering the period between 1977 and 1981. The incidence of hydatidiform mole was 1 in 77 pregnancies. The incidence of malignant trophoblastic disease was 1 in 185 pregnancies. Of the 406 cases of hydatidiform mole, 22.9% became malignant. Patients of 24 years of age or younger had a higher risk of getting hydatidiform mole (P less than 0.05) compared to older patients. The risk of becoming malignant increased with age and became evident after 40 years of age. Parity 1 or less was associated with a higher risk of getting hydatidiform mole (P less than 0.05), but had no influence on hydatidiform mole becoming malignant. The influence of blood group was not so clear, although there was a tendency for moles to occur more frequently in patients with blood groups A or B. By contrast, there was a tendency for the change into malignancy to occur more frequently in women with blood groups B or O. Gestational age had no influence towards the change into malignancy or metastasis. Uterine size (greater than 20 weeks gestation) correlated with the progression of hydatidiform mole into malignancy. However, subsequent metastasis was not influenced by the size of the uterus. It was found that 76.4% of malignant trophoblastic diseases originated from hydatidiform moles, 12.4% from abortions, 9.5% from normal deliveries, and 1.2% from ectopic pregnancies. Non-hydatidiform moles had a slightly greater risk for metastasis, although this was not significant. Hydatidiform mole in histologic stages II or III (Hertig-Mansell classification) had a significantly greater tendency (P less than 0.05) to become malignant than in stage I.

Epidemiology of trophoblast disease in Africa--Lagos

Trophoblast neoplasm cases at the Lagos University Teaching Hospital in the two-year period, 1980-1981, have been reviewed. An apparent increased incidence of 1 in 184 deliveries for hydatidiform mole and 1 in 299 deliveries for choriocarcinoma has been noted when compared with a previous review. An association of hydatidiform mole with age and parity was observed in this study. Among patients with hydatidiform mole, 27 percent also had pseudotoxemia and in one case this progressed to eclampsia. In the case of choriocarcinoma, increased parity appears to be associated with a higher mortality. The relatively higher mortality of 31 percent from this study could be related to the long duration of symptoms before diagnosis and treatment, and a plea is made to the general medical practitioners for a better referral system, although the need to create an increased awareness of the clinical symptoms of this disease in the community is also very much desirable. A collaborative study of the epidemiology of this disease in Nigeria is advocated.

Discrepancies in the histological diagnosis of hydatidiform mole

Sections of tissue from 256 patients on which a histological diagnosis of hydatidiform mole had been made were reviewed by a visiting pathologist. There was agreement between the reporting pathologists and the visiting pathologist in only 55.1 per cent of cases, a less severe diagnosis was made by the visiting pathologist in 42.2 per cent of cases. The disagreement was as high as 66.6 per cent with pathologists who rarely worked in the gynaecological field. This study casts serious doubt on the consistency of the histological diagnosis of hydatidiform mole made in any one laboratory and between different laboratories. It is suggested that in epidemiological studies the diagnosis should be made by a panel of pathologists using strict histological criteria and in an individual laboratory diagnosis should be made or confirmed by a pathologist experienced in gynaecological pathology.