Differentiating complete hydatidiform mole and coexistent fetus and placental mesenchymal dysplasia: A series of 9 cases and review of the literature

Abstract

To identify the differentiating features in clinical presentation, management, and maternal/fetal outcome in complete hydatidiform mole and coexistent fetus compared with placental mesenchymal dysplasia. Between 1997 and 2015, five women with complete hydatidiform mole and coexistent fetus and four women with placental mesenchymal dysplasia were managed at the University of California San Francisco. Clinical features were analyzed and compared with previously published data. Of the five cases of complete hydatidiform mole and coexistent fetus, two had live births. β-hCG levels were > 200,000 IU/L in all cases. On imaging, a clear plane between the cystic component and the placenta favored a diagnosis of complete hydatidiform mole and coexistent fetus. None of the patients went on to develop gestational trophoblastic neoplasia (GTN), with a range of follow-up from 2 to 38 months. Combining this data with previously published work, the live birth rate in these cases was 38.8%, the rate of persistent GTN was 36.2%, and the rate of persistent GTN in patients with reported live births was 27%. Of the four cases of placental mesenchymal dysplasia, all four had live births. One patient developed HELLP syndrome and intrauterine growth restriction; the remaining three were asymptomatic. Maternal symptoms, fetal anomalies, β-hCG level, and placental growth pattern on imaging may help differentiate between complete hydatidiform mole and coexistent fetus and placental mesenchymal dysplasia. There was not an increased risk of gestational trophoblastic neoplasia in patients with complete hydatidiform mole and coexistent fetus who opted to continue with pregnancy.

Keywords: GTN; Obstetric imaging; Placental mesenchymal dysplasia; Twin mole.

Fig. 1

A. Axial T2 weighted MRI of the abdomen and pelvis demonstrating twin molar pregnancy. Normal placenta (P), Molar pregnancy (M), and Fetus (F). B: Axial T2 weighted MRI of the abdomen and pelvis demonstrating PMD. There is no clear plane separating the cystic component and normal placenta. Placenta (P), Fetus (F). C: Transverse abdominal ultrasound demonstrating twin molar pregnancy. Normal placenta (P), Molar pregnancy (M), and Fetus (F). D: Transverse abdominal ultrasound demonstrating PMD. Again no clear plane is seen between the cystic component and normal placenta. Placenta (P).

Fig. 1

A. Axial T2 weighted MRI of the abdomen and pelvis demonstrating twin molar pregnancy. Normal placenta (P), Molar pregnancy (M), and Fetus (F). B: Axial T2 weighted MRI of the abdomen and pelvis demonstrating PMD. There is no clear plane separating the cystic component and normal placenta. Placenta (P), Fetus (F). C: Transverse abdominal ultrasound demonstrating twin molar pregnancy. Normal placenta (P), Molar pregnancy (M), and Fetus (F). D: Transverse abdominal ultrasound demonstrating PMD. Again no clear plane is seen between the cystic component and normal placenta. Placenta (P).

Fig. 1

A. Axial T2 weighted MRI of the abdomen and pelvis demonstrating twin molar pregnancy. Normal placenta (P), Molar pregnancy (M), and Fetus (F). B: Axial T2 weighted MRI of the abdomen and pelvis demonstrating PMD. There is no clear plane separating the cystic component and normal placenta. Placenta (P), Fetus (F). C: Transverse abdominal ultrasound demonstrating twin molar pregnancy. Normal placenta (P), Molar pregnancy (M), and Fetus (F). D: Transverse abdominal ultrasound demonstrating PMD. Again no clear plane is seen between the cystic component and normal placenta. Placenta (P).

Fig. 1

A. Axial T2 weighted MRI of the abdomen and pelvis demonstrating twin molar pregnancy. Normal placenta (P), Molar pregnancy (M), and Fetus (F). B: Axial T2 weighted MRI of the abdomen and pelvis demonstrating PMD. There is no clear plane separating the cystic component and normal placenta. Placenta (P), Fetus (F). C: Transverse abdominal ultrasound demonstrating twin molar pregnancy. Normal placenta (P), Molar pregnancy (M), and Fetus (F). D: Transverse abdominal ultrasound demonstrating PMD. Again no clear plane is seen between the cystic component and normal placenta. Placenta (P).

Fig. 2

A: Villi from twin conception of a non-molar gestation (uniform small villi, left half of image) and a complete mole (massively enlarged villi with cisterns and trophoblast proliferation, right half of image). B: Villi from placental mesenchymal dysplasia shows massively enlarged villi and a background of uniform small normal villi. In contrast to the complete mole (Fig. 2A) there are no cisterns or trophoblast proliferation. C and D: The villous trophoblast exhibits exuberant proliferation in complete mole (Fig. 2C) whereas there is no trophoblast proliferation in placental mesenchymal dysplasia (Fig. 2D).

Fig. 2

A: Villi from twin conception of a non-molar gestation (uniform small villi, left half of image) and a complete mole (massively enlarged villi with cisterns and trophoblast proliferation, right half of image). B: Villi from placental mesenchymal dysplasia shows massively enlarged villi and a background of uniform small normal villi. In contrast to the complete mole (Fig. 2A) there are no cisterns or trophoblast proliferation. C and D: The villous trophoblast exhibits exuberant proliferation in complete mole (Fig. 2C) whereas there is no trophoblast proliferation in placental mesenchymal dysplasia (Fig. 2D).

Fig. 2

A: Villi from twin conception of a non-molar gestation (uniform small villi, left half of image) and a complete mole (massively enlarged villi with cisterns and trophoblast proliferation, right half of image). B: Villi from placental mesenchymal dysplasia shows massively enlarged villi and a background of uniform small normal villi. In contrast to the complete mole (Fig. 2A) there are no cisterns or trophoblast proliferation. C and D: The villous trophoblast exhibits exuberant proliferation in complete mole (Fig. 2C) whereas there is no trophoblast proliferation in placental mesenchymal dysplasia (Fig. 2D).

Fig. 2

A: Villi from twin conception of a non-molar gestation (uniform small villi, left half of image) and a complete mole (massively enlarged villi with cisterns and trophoblast proliferation, right half of image). B: Villi from placental mesenchymal dysplasia shows massively enlarged villi and a background of uniform small normal villi. In contrast to the complete mole (Fig. 2A) there are no cisterns or trophoblast proliferation. C and D: The villous trophoblast exhibits exuberant proliferation in complete mole (Fig. 2C) whereas there is no trophoblast proliferation in placental mesenchymal dysplasia (Fig. 2D).