The tumor is composed of small, uniform, round acini and tubular structures separated by scant stroma. The lining epithelial cells are uniform with hyperchromatic nuclei and hae scant cytoplasm.

• 肿瘤的胞核小而圆，大小一致，形成管状结构，与周围少量的间质分隔开。瘤细胞大小均匀，核深染，胞浆少。