The ultrasound diagnosis of hydatidiform mole.

Experience with ultrasound compound 'B' scanning in 18 cases of hydatidiform mole is presented. The scan appearances are analysed with respect to the presence or absence of transonic areas, and to the uniformity of echogenicity elsewhere in the uterus. The differential diagnosis is discussed. The commonest appearance seen in a hydatidiform mole is the combination of multiple small transonic areas with uneven echogenicity in the remainder of the uterine cavity. The condition most likely to cause diagnostic confusion is early normal pregnancy with a bulky decidua, but incomplete abortion and uterine fibroid may also be confused with hydatidiform mole.