[Cytogenetic, morphological and clinical studies on partial hydatidiform moles].

To establish the clinical management of partial moles, cytogenetic, morphological and clinical studies of 57 partial moles, including three twin cases, were performed. The karyotypes of the 54 singletons were 46 triploid and eight diploid. By examining the genetic markers, two of the diploid moles were proved to be derived from normally fertilized conceptuses. Molar tissues from two twin cases had a 46,XX karyotype of androgenetic origin, while the normal placenta and fetus were derived from normal conceptuses. An embryo (or fetus) (26.9%) or only an umbilical cord (9.6%) was found in some triploid and diploid moles. Vessels with erythroblasts were also recognized in most cases. In addition, there was a positive correlation between cyst formation and gestational length in triploid conceptuses. These findings suggest that triploid partial moles are an altered form of missed abortion. The mole became invasive in one twin case with an androgenetic mole, but the remaining cases had uneventful courses. These results indicate that partial moles can be divided into three groups: Triploid, Diploid derived from normally fertilized conceptus, Binovular twins with androgenetic mole, and that, except for those in group 3, partial moles have no malignant potential and require no intensive follow-up.