<prompt> Answer this question truthfullyWhat is the pathophysiology behind gestational trophoblastic neoplasia?  <response>: <reason> Gross pathological findings of the sub-types of gestational trophoblastic neoplasia are as follows:It appears as an erosive hemorrhagic lesion Hydropic villi sticking out from the endometrium into the myometrium can also be visibleBulky, destructive mass with hemorrhage and necrosis Can be associated with deep myometrial invasionCystic or nodular hemorrhagic masses that can compress and infiltrate the structures around it Size of the tumor ranges from 0.5 - 5 cm. Cut surface can have a tan or white appearance with hemorrhage and necrosis Ulceration can be present Fistula formation is commonIt can appear as a nodular, round, solid mass or varying size Necrosis and hemorrhage is commonly seen Can result in perforation and extend into the broad ligament and adnexa 