Hydatidiform mole with co-existent fetus.

Co-existence of hydatidiform mole and fetus is a rare condition, but one in which the radiologist, through ultrasound, can play an important role in diagnosis. The typical patient, with no pre-existing hypertension or renal disease, develops severe pre-eclampsia in the second trimester with elevated gonadotropin levels. Ultrasound shows a large placenta containing varying numbers of sonolucent spaces, associated with a live or dead fetus. This condition appears to be a separate entity from classical hydatidiform mole both pathologically and prognostically. It should also be differentiated from simple hydatidiform swelling which does not have the associated clinical picture.