Trophoblastic growths: morphologic aspects and taxonomy

The hydatidiform mole-gestational choriocarcinoma complex constitutes a graft qua tumor whose natural invasion, rejection and resolution share features of normal pregnancy and of neoplasms of other tissues. Trophoblastic neoplasms sometimes arise from morphogenetically abnormal chorions, notably the "partial mole," among others. Thus, they provide another demonstration of the association of teratogenic and carcinogenic events. Gestational choriocarcinoma is a complication of pregnancy, not a sequel to it. Although these tumors may arise from the trophoblast of any pregnancy, presenting symptoms during gestation or following it, they are much rarer than the innocuous conditions, normal and abnormal, with which they may be confused. A bone fide malignant neoplasm is less likely to be misdiagnosed as a banal phenomenon than is the reverse. Morphologically, the trophoblast is the key, and emphasis should be placed on its behavior. Taxonomy should follow suit, employing the simple, explicit terms chorioma and choriocarcinoma, graded to express the neoplastic attributes of the constituent epithelium.