DNA polymorphism analysis of a case of complete hydatidiform mole coexisting with a fetus.

A complete hydatidiform mole coexisting with a fetus is a rare condition. The diagnosis is often difficult because of the morphological similarity to a partial mole, but is crucial to management in the postmolar course. We present a case of molar pregnancy coexisting with a fetus in which DNA polymorphism analysis revealed a different genetic origin for the fetal and molar parts. This is the only known case of a complete mole in a twin pregnancy complicated by pre-eclampsia followed by maternal pulmonary oedema. During follow-up, the patient developed a clinically invasive mole which was successfully treated with chemotherapy. In this case, genetic analysis unequivocally diagnosed a twin pregnancy consisting of a complete hydatidiform mole and a fetus.