Gestational trophoblastic neoplasms: morphologic considerations

Abnormal trophoblastic proliferation is the hallmark of a spectrum of lesions constituting the gestational trophoblastic neoplasms. Rapid proliferation, infiltration, vascular invasion, hematogenous dissemination, and spontaneous regression are features of both normal and neoplastic trophoblast. Trophoblastic hyperplasia without hydrops, hydatidiform mole, invasive mole, and gestational choriocarcinoma are related lesions, characterized by increasingly aberrant trophoblastic growth and worsening prognosis, if untreated. Difficulties in diagnosis may arise with respect to the normal early implantation site, the hydropic abortus, and postgestational, involuting, residual trophoblast. Histologic grading or hydatidiform moles is relevant to their prognosis and biologic behavior. Trophoblastic neoplasia may begin at any stage of pregnancy or puerperally with immediate or late and local or distant manifestations in the mother or the child. Cognizance of the capricius potential behavior of trophoblast permits successful management of its proliferative lesions, monitored by serial measurement of gonadotropin secretion.