Complete hydatidiform mole coexisting with a live twin fetus (CHMF) is a rare occurrence occurring in 1 in 22,000 to 1 in 100,000 pregnancies according to authors [1],[2],[3],[4]. Given the risks of immediate and long-term maternal complications, it should not be misdiagnosed. Moreover, this presents both the physician and the couple with a significant dilemma between immediate intervention and expectant management. We report the case of a patient hospitalized in the maternity ward of the university hospital Abderrahim Harouchi in Casablanca, presenting a complete hydatidiform mole coexisting with a live twin fetus that resulted in the termination of pregnancy.

We report the case of a 43-year-old female patient, VG IIIP (3 previous normal deliveries and one miscarriage), having no underlying medical condition, no drug history, and no consanguinity, was admitted for second trimester abnormal uterine bleeding after 20 weeks of amenorrhea, brought in an ambulance from home. This was her second examination and sonography during this pregnancy, the first being in the first trimester (10 weeks of amenorrhea) where the physician, a general doctor missed the diagnosis. Clinical examination found a conscious, hemodynamically stable patient, the cervical canal was slightly open with uterine bleeding and a fundal height greater than gestational age. The ultrasound revealed a bichorial twin pregnancy: two gestational sacs, one with a living fetus of 21SA, another containing an amniotic cavity with a multi-cystic portion suggestive of molar tissue measuring 14 cm (Figure 1). Laboratory test carried showed a level of chorionic gonadotropin hormone (beta-hCG) at 1788,900 mIU/L, without anemia (hemoglobin at 11.5 g/dL), without hyperthyroidism (TSH at 1.18 mIU/L) or diabetes (fasting blood sugar at 0.72 g/dL). Medical termination of pregnancy was indicated: induction of labor with 400 mg of misoprostol intravaginally with no change in cervix dilatation for 6 hours, followed by endo-uterine aspiration. This decision was taken after consultation with the patient and her family, and explaining to them the possible maternal and fetal complications and the poor prognosis of this combination, in particular the risk of progression into a gestational trophoblastic tumor. The expulsion product was in the form of a living fetus of 21SA with its own trophoblast associated with a 14 cm vesicular mass (Figure 2 and Figure 3). The histological examination found a complete hydatidiform mole. Monitoring of the plasma beta-hCG curve revealed a regression of the level after expulsion with absence of myometrial invasion on the follow-up ultrasound, as well as a negativation of beta-hCG, after one month.

Complete hydatidiform mole coexisting with a live twin fetus is a rare entity, with a difficult management given the complications such as fetal death, bleeding, pre-eclampsia, hyperthyroidism, and the risk of progression to a gestational trophoblastic tumor [5]. Diagnosis is based on the clinical features, serum human chorionic gonadotropin (HCG) level, and ultrasound; and will be confirmed after anatomopathological study. The accurate diagnosis isn’t usually made before the end of the first trimester or the beginning of the second trimester, and generally CHMF is diagnosed later than a molar pregnancy in 71% of cases [2],[3]. Clinically, the signs are not very specific and correspond to those of a simple complete hydatidiform mole (CHM) [6]. The ultrasound shows two distinct placental masses, one of normal appearance associated with a healthy fetus, the other of multi-cystic molar appearance with no embryonic element [7]. We can also find functional ovarian cysts, often bilateral, in 25% of cases [8]. In our case, the diagnosis was delayed. The main differential diagnosis of a twin pregnancy with CHM and a healthy fetus is the partial hydatidiform mole (MHP), which must be distinguished from it because the management is completely different [4]. In our case, the diagnosis of CHM was essentially based on the laboratory results and the ultrasound. The management raises an ethical issue: is it possible to continue the pregnancy despite the risk of obstetric or oncological complications?

In 38% of cases, fetal viability is possible. The median gestational age reached at delivery is 35 weeks (25–41 weeks) [9]. This therapeutic management is not without complications, the maternal and fetal prognosis are usually at risk, with 21% of metrorrhagia, a major risk of postpartum hemorrhages, 6% of pre-eclampsia, 43% of late spontaneous abortions, 13% death in utero and prematurity [3],[9]. As well as gestational trophoblastic tumor occurring in 50–57% cases [10]. Given the poor maternal prognosis of CHMF, and when the diagnosis is made early, in the first or second trimester, termination of pregnancy is generally considered the most acceptable course of action [6], as was the case for our patient, whose pregnancy was terminated at 20 weeks. The decision to maintain or terminate the pregnancy isn’t an easy decision to make, and has to be guided by the gestational age, the symptoms, the presence or absence of fetal growth restriction or a malformation, as well as the couple’s wishes after thorough information. The patient should undergo a careful clinical, biological, and ultrasound monitoring if the pregnancy is maintained. If the pregnancy is terminated, monitoring is essentially based on the dosage of HCG once a week until negativation [6], then once a month for a year with effective contraception [7]. Persistence of elevated HCG levels correlates with a higher risk of gestational trophoblastic tumor [1],[8]. In our case, with a follow-up of 16 months, the evolution was favorable, marked by a regression of the HCG levels without a development of a gestational trophoblastic tumor.

Complete hydatidiform mole coexisting with a live twin fetus remains a rare pathology, with a high risk of complications for the mother and the fetus. Diagnosis is possible since the first trimester, that’s why the first trimester examination and sonography should be a very meticulous exam performed by an experimented physician. With the development of ultrasound and Doppler, more and more teams lean toward the continuation of pregnancy, but the dilemma remains and the decision should always include the couple and a thorough explanation of all the risks.