Flow cytometric and clinicopathologic study of 197 hydatidiform moles with special reference to the significance of cytometric aneuploidy and literature review

In order to evaluate the significance of cytometric aneuploidy in molar placentas, we analyzed 197 hydatidiform moles by flow cytometry using formalin-fixed, paraffin-embedded tissues. Of 150 complete moles (CMs), 110 were diploid, 26 were tetraploid, and 14 were aneuploid (non-triploid/tetraploid aneuploid). Of 47 partial moles (PMs), 44 were triploid and 3 were diploid. We could not find any histologic differences among the diploid, tetraploid, and aneuploid CMs. We found that flow cytometric DNA analysis was very helpful to differentiate CM from PM. Persistent diseases developed in 12 of 69 CMs (17.4%) (9 of 47 diploid and 3 of 14 tetraploid CMs) and in none of 26 PMs (0%). Four diploid and 2 tetraploid CMs were invasive and one each with diploid and tetraploid CM developed choriocarcinoma and none of 8 aneuploid CMs had sequelae; however, there was no correlation between DNA ploidy and clinical outcome in the CMs. These results suggest that cytometric aneuploidy (non-diploidy) in CMs is not an independent predictor of persistent disease.