Cytogenetic and clinical features of placental moles: synopsis and update.

Abnormalities of fertilization are responsible for two types of placental moles. This synopsis of the two syndromes includes definition, relative incidence, mechanism of fertilization, and clinical course. Controversy regarding the comparative course has diminished with the recognition that partial moles can have sequelae requiring chemotherapy, although less frequently than complete moles. An important subgroup of complete moles is dispermic and heterozygous (usually 46,XY), and these have a disproportionately high rate of postmolar complications. Recommendations are made for routine cytogenetic study of moles in order to foster precision in classification and search for heterozygosity in complete moles. A technique is given for isolation and promotion of growth in vitro of molar trophoblastic cells. Additional information about the two syndromes is needed, a challenge for cytogeneticists.