Cell ploidy in molar placental disease.

Molar disease of the placenta is associated with cystic change in the villi. The cysts may be from 5–20+ mm in diameter. This disease has been described in association with triploid and diploid cell lines and with and without an accompanying embryo or fetus. It may be followed by malignant change and invasive chorio-carcinoma. In order to investigate the association between cell ploidy, embryonic development and subsequent malignancy, a detailed study of 30 conceptuses with molar disease was made, with the accompanying maternal history and follow-up. The cell ploidy was determined by measurement of nuclei by a cytoscan light microscope connected to a computer program as has been previously described. Diploid cell lines were not found with embryonic or fetal development. Triploid cell lines were always associated with an embryo or fetus. Triploidy is not associated with hyperplastic changes in the trophoblast. These results are presented and discussed.