Ultrastructure of molar trophoblast. Observations on hydatidiform mole and chorioadenoma destruens.

The ultrastructure of molar trophoblast is described in hydatidiform mole and chorioadenoma destruens. Villous molar trophoblast exhibits only minor deviations from normal early villous trophoblast. Invasive trophoblast of chorioadenoma destruens shows features of more-active cell growth, multiplication, differentiation, and degradation. Evidence for evolution of highly differentiated syncytial trophoblast via intermediate stages from primitive undifferentiated cytotrophoblast is confirmed. Cytoplasmic inclusions resembling virus-like particles, observed in chorioadenoma destruens, have not been hitherto described in normal or pathologic trophoblast.