EARLY COMPLETE HYDATIDIFORM MOLES CONTAIN INNER CELL MASS DERIVATIVES

In four cases of early complete hydatidiform moles, confirmed to be an drogenetic in origin by DNA studies, we have identified non-chorionic inner cell mass derived structures which are not commonly observed in specimens of later gestational age, These structures include nucleated red blood cells, endothelial cells, stromal macrophages, amnion and y olk sac, The latter four structures were confirmed by specific immunoc ytochemical stains. Recognition that such structures can accompany com plete hydatidiform moles has both theoretical and practical significan ce. From a theoretical perspective, it demonstrates that the maternal genome is not required for the initiation of amniogenesis, development of the yolk sac, vasculogenesis, or hematopoiesis, From a practical p erspective it emphasizes that complete hydatidiform moles, with their markedly increased risk of subsequent choriocarcinoma, cannot be exclu ded based on the finding of ''fetal structures.'' (C) 1997 Wiley-Liss, Inc.