Abstract

Many investigators were interested in the pathogenesis and the relationship between microscopical features and clinical behavior of hydatidiform mole. Trophoblastic cells in the trophoblastic disease were intensively examined histologically, ultrastructurally, immunohistochemically, and with hormone assay method, etc. But ultrastructural study on the stroma of hydatidiform mole was scarcely reported. In this paper, hydatidiform mole was examined at light and electron microscopic levels, with emphasis on the stroma. The results were as follows: 1) Hydropic degeneration of H-mole is more severe in the center of stroma and is not related with the degree of trophoblastic proliferation. Hofbauer cell and vascular structure are extremely rarely observed in the periphery of stroma which has relatively preserved cellular components. 2) Basement membrane is sometimes separated from trophoblastic layer. Degenerated cells in the stroma contain vacuoles, autophagosomes, and lipid droplets. Collagen is abundant in the loose interstitium. Hofbauer cells have no lysosome or phagosome. Vascular lumen is patient and endothelial cells are degenerated. From the above results, H-mole may be produced due to abnormal changes of trophoblasts and stromal changes may be a secondary process, so called autolysis. Hofbauer cells are not engaged in the stromal degeneration and may be different from usual tissue macrophages.

• Keywords: H-mole;trophoblast;stromal change;degenerated cells;basement membrane;Hofbauer cell;vessel