Flow cytometric diagnosis of partial mole.

Summary To differentiate histologically partial hydatidiform moles (PM) and complete hydatidiform moles (CM) may be difficult. Cytogenetic studies have shown that PMs often had a triploid karyotype while CMs were always diploid. We assessed the DNA content of 31 paraffin -embedded cases of tropboblastic disease with flow cytometry. Twenty-four cases were histologically diagnosed as PM, 3 cases as CM; the others as bydropic abortion (2 cases), cboriocarcinoma (1 case), and perisistent tropboblastic disease (1 case). Four normal term placentas were used as'diploidy controls. In 9 cases the results of the cytogenetic analysis were availabile. All placental specimens included also maternal tissue as an internal control. Eight of the 24 histologically diagnosed PMs were triploid; there was agreement in 8 cases out of 9 (90 %) between the flow cytometric analysis and the karyotypic determination of ploidy. All normal controls as well as the bydropic abortion, the CM and the persistent tropboblastic disease were. diploid. Abnormal content of DNA (DI=1.3) was observed in the choriocarcinoma. Our results show that flow cytometric analysis of DNA content is a reliable and fast method of diagnosing PM on paraffin-embedded material.