The criteria for diagnosing GTN are all

Theca lutein cysts may be felt in the ovaries in about 50%.These cysts are due to over stimulation of luteal elements by large amount of circulating hCG secreted by the proliferating trophoblast.Larger moles are more likely to be associated with cysts.Persistent trophoblastic disease is more likely in women with Theca lutein cysts.(refer pgno:170 sheila textbook of obstetrics 2 nd edition)