[Histopathological characteristics of stromal cells in trophoblastic disease]

The histopathological characteristics of stromal cells in trophoblastic diseases remain unknown, though determination of malignancy depends on the existence of stromal elements in villi. Thus, we tried to clarify the characteristics and role of stromal cells in the development of diseases. The mitosis index (MI) of stromal cells and cytotrophoblasts, and the frequency of vessels observed in the stroma were examined. The results were as follows: 1) Complete moles were characterized by high MI values for stromal cells and cytotrophoblasts. They were similar to the ones from normal villi. 2) In partial moles, the MI values for both cells were remarkably low. 3) Invasive moles showed low stromal MI and high cytotrophoblastic MI values. 4) The frequency of blood vessels observed in the stroma was low in complete and invasive moles, though it was high in partial moles. The present results which showed histopathological differences in stromal elements in partial and complete moles, may correspond to the difference in their pathogenesis. And it is possible to assume that the decrease in stromal MI values in invasive mole play an important role in the abnormal proliferation of trophoblasts.