2000 Volume 12 Issue 4 Pages 351-359
A case of endometrial stromal nodule showing immunoreactivity for α-SMA in a majority of the tumor cells, with smooth muscle as a minor component, is reported. This tumor was mainly composed of diffuse proliferation of uniform cells resembling those of endometrial stroma, and included blood vessels resembling arteria spiralis and prominent perivascular whorl arrangement of the tumor cells. In addition, the smooth muscle component was detected by light microscopy. Immunohistochemically, many tumor cells showed α-SMA positivity. In previous studies of endometrial stromal tumor, we showed a variety of combinations and proportions of positivity for several myogenic antibodies, and suggested that endometrial stromal tumor is heterogeneous based on immunoreactivity for several myogenic antibodies. In the present case, a distinction between endometrial stromal nodule and cellular leiomyoma was necessary. We concluded that light microscopic findings, including staining with hematoxylin and eosin, are the most important means for differential diagnosis of this tumor.
