Diagnosis of molar pregnancy and persistent trophoblastic disease by flow cytometry

Abstract

Histopathological assessment and flow cytometric analyses were carried out on 32 placentas (representative of each trimester) and 88 molar pregnancies. Three first trimester placentas were triploid, and the remaining 29 placentas were diploid. Of the 88 cases originally diagnosed as molar pregnancies, 26 were triploid (2 complete moles, 20 partial moles, and 4 hydropic abortions); 59 were diploid (46 complete moles, 10 partial moles, 3 hydropic abortions); 1 was tetraploid (partial mole); and 2 were DNA aneuploid (1 partial mole, 1 complete mole). A significantly increased hyperdiploid fraction (a measure of cell proliferation) was detected in diploid complete moles (p < 0.0001) and cases of persistent trophoblastic disease (p < 0.001) when compared with diploid placentas and diploid partial moles. All 7 cases of established persistent trophoblastic disease, for which follow up was available, were diploid and showed high hyperdiploid fractions within the range for diploid complete moles. These findings suggest that flow cytometric DNA measurements may be an important aid in the diagnosis of molar pregnancy. The high degree of cell proliferation found in this study may explain the premalignant potential of complete hydatidiform moles.