However, about 25% of cases exhibit frank malignant features of prominent nuclear pleomorphism (as in this case), mitoti然而，大约25%的病例显示恶性特征诸如明显核多型现象（比如此例）、核分裂活性或者坏死。
It is much more cellular and the cells have much more pleomorphism and hyperchromatism than the benign leiomyoma.与良性的平滑肌瘤相比，其细胞丰富，细胞异型性明显，深染。