Abstract

Twin conceptus of a complete hydatidiform mole (CHM) and a normal fetus are rare but are important because of diagnostic difficulty, problems related to twin pregnancy, and high risk of persistent gestational trophoblastic tumor. Recently, we experienced one case of twin pregnancy consisting of a CHM and a normal fetus. A 26-year-old woman complained of vaginal bleeding. She had evidences of pregnancy-induced hypertension. A male fetus was delivered at 20 gestational weeks. The placenta demonstrated vesicles of molar change separated from normal placenta. Microscopically, the molar villi disclosed diffuse hydropic swelling with circumferential trophoblastic proliferation. DNA flow cytometric analysis showed diploid patterns in both molar and normal placental tissues. Fluorescent in situ hybridization in paraffin-embedded tissue presented that normal placental villi hybridized with X- and Y-chromosome probes (46, XY), while molar villi hybridized with X-chromosome only (46, XX). Thus, dizygotic twinning was confirmed because sex differences were shown between molar villi and normal placental villi. Follow up beta-hCG was within normal range after delivery.

• Keywords: Complete hydatidiform mole;Twin;Fluorescent in situ hybridization