Ultrasound finding of a pregnant female shows 'snowstorm' appearance which is characteristic of hydatidiform mole. MOST common gestational trophoblastic disease following hydatidiform mole is:

Invasive mole: This is a common manifestation of gestational trophoblastic disease (GTN) characterized by whole chorionic villi that accompany excessive trophoblastic overgrowth and invasion. These tissues penetrate deep into the myometrium, sometimes to involve the peritoneum, adjacent parametrium, or vaginal vault. Such moles are locally invasive, but generally lack the pronounced tendency to develop widespread metastases typical of choriocarcinoma. Invasive moles originate almost exclusively from complete or paial molar gestations. Ref: Hoffman B.L., Schorge J.O., Schaffer J.I., Halvorson L.M., Bradshaw K.D., Cunningham F.G., Calver L.E. (2012). Chapter 37. Gestational Trophoblastic Disease. In B.L. Hoffman, J.O. Schorge, J.I. Schaffer, L.M. Halvorson, K.D. Bradshaw, F.G. Cunningham, L.E. Calver (Eds), Williams Gynecology, 2e.