Complete hydatidiform mole coexisting with a viable fetus in a twin pregnancy – a case report

Abstract

Cases of twin pregnancy where a normal viable fetus coexists with a hydatidiform mole have been reported rarely. The incidence ranges from 1 in 20,000 to 1 in 1, 00000 pregnancies. This condition is a consequence of dizygotic twinning. The fetus, in such cases, is chromosomally normal as opposed to the mole. We report one such case where a twin pregnancy consisted of a viable 12 week old fetus and its normally formed placenta coexisting with a complete hydatidiform mole in the other twin sac. There is a greater risk of persistent trophoblastic disease (50– 60%) in cases where a complete mole coexists with a fetus as opposed to single molar pregnancies (14%).By reporting this case, we strive to highlight the need for more vigilant obstetric surveillance in such patients by serial beta-HCG estimation, and sonographic evaluation in conjunction with doppler and MRI when available.