A challenging case of twin pregnancy with complete hydatidiform mole and co-existing normal live fetus – A case report and review of the literature

Hydatidiform mole coexisting with a normal live fetus in a twin pregnancy is extremely rare. Management of these cases is challenging due to the risk of severe antepartum and post-partum complications. Herein, we report the case of a 24-year-old gravida 2 para 1 who presented at 28 weeks gestation with severe preeclampsia, vulvar edema and a serum β-HCG of 285,000 IU/mL. Ultrasonography demonstrated a single live intra-uterine pregnancy with concurrent hydatidiform mole. Conservative management with magnesium sulfate and anti-hypertensive medications was initiated however the patient developed HELLP syndrome and required urgent delivery at 33 weeks. Copious molar tissue was removed from the uterus during delivery. Four weeks post-partum, her β-HCG had dropped to 14,000 IU/ml and continued to decline at 6 weeks (2900 IU/ml). However, at eight weeks, it increased to 3500 IU/ml and the patient was treated with nine cycles of intramuscular methotrexate. Current guidelines for management of a twin pregnancy with coexistent mole recommend close clinical monitoring if the mother and fetus are stable and urgent delivery in the setting of complications. During the postpartum period, careful follow up with clinical evaluation and serial serum β-HCG is important for the diagnosis and treatment of persistent trophoblastic disease.