It may be a ductal lesion. This is why we need to stain.

E-cad is membranous stain for ductal lesions. Your photos of stains are not clear. Can you show us the photos with high power and high quality? Do you have negative control? Can you do P120 stain?

thanks

 免疫组化结果很有意思，好像确实是E-Ca阳性。那么应该是导管癌了。

可是HE图像也确实有细胞粘附性丧失，还有胞质内空泡。小叶癌的特征也不能视而不见。除非有一种可能：制片不佳产生的粘附性差（假象），而质空泡也可见于导管癌。

如果是我的病例，我可能会报：浸润性乳腺癌伴部分浸润性小叶癌特征，但免疫组化示E-Ca阳性较符合浸润性导管癌。不影响分级，也不影响临床处理。

谢谢楼主和各位老师。

好病例！谢谢

 Invasive ductal carcinoma and DCIS.

H & E appears to have invasive lobular carcinoma, but E-Cad exluded that.  Some ductal Ca has poor glandular formation and thus mimics lobular ca.

 May be ductal ca. However I cannot evaluate if the stains of tumor cells are weaker  than normal ductal epithelial cells based on photos.

Remember that E-cadherin can be negative or reduced stain for E-cad