Fig. 4

Histopathologic findings of the right axillary lymph node metastasis. A Hematoxylin and eosin staining showing a poorly differentiated metastatic tumor with nuclear pleomorphism and high mitotic activity (200 × magnification). B–D Immunohistochemical staining revealing that the tumor cells are positive for ER, GCDFP-15, and GATA3 (200 × magnification). These findings suggest that the metastasis is derived from the breast carcinoma. ER, Estrogen receptor; GCDFP-15, gross cystic disease fluid protein-15; GATA3, GATA binding protein 3