Gestational Trophoblastic Disease and Related Lesions

Abstract

Gestational trophoblastic disease (GTD) encompasses a heterogeneous group of lesions, including hydatidiform mole, invasive mole, choriocarcinoma, and placental site trophoblastic tumor, that are characterized by an abnormal proliferation of trophoblastic tissue. Some of these lesions are true neoplasms, whereas others represent abnormally formed placentas with a predisposition for neoplastic transformation of the trophoblast. The literature on this subject is extensive but sometimes confusing because of inconsistencies in classification and terminology. In fact, the necessity of a morphologic classification has been questioned, since current management is largely medical and in the case of trophoblastic disease following a mole, often conducted in the absence of a histological diagnosis. Thus, all trophoblastic lesions are frequently combined under the rubric of GTD without applying specific pathological terms. Recent cytogenetic and immunocytochemical studies demonstrate profound differences in the etiology, morphology, and clinical behavior of various forms of the disease, however. These studies underscore the importance of a uniform histological classification to facilitate standardized reporting of data and to ensure appropriate clinical management. Nonetheless, the term GTD has clinical utility, since the principles of human chorionic gonadotropin (hCG) monitoring in follow-up and the chemotherapy of metastatic or persistent disease are similar for all these entities.147.