Sex chromatin pattern in hydatidiform mole

Ninety cases of hydatidiform mole were investigated for the presence of the sex chromatin body. Well-defined heterochromatic bodies were found in every section. In 79 cases (88 per cent) 15 or more chromatin-positive cells were identified per 100 cells counted. Previous investigations have shown that these findings cannot be explained on the basis of polyploidy. It is suggested that two cell lines develop in hydatidiform mole, one line representing the union of the sperm and ovum; the second by endoreduplication of the second polocyte. This could account for the coexistence of a mole and fetus, for the mole alone, and for "molar degeneration of the placenta." Again, in all these instances the sex of the mole is predominantly female.