Rare Presentation of Metastatic Lobular Breast Carcinoma Involving Clear Cell Renal Cell Carcinoma

Figure 4

A panel of immunohistochemical stains performed supports the morphologic impression of two distinct neoplasms—ccRCC and metastatic lobular breast carcinoma. The neoplastic cells of the ccRCC are negative for GATA3 and ER, but immunoreactive for ECAD and PAX-8. The neoplastic cells of the metastatic lobular breast carcinoma are immunoreactive for GATA3 and ER, but negative for ECAD and PAX-8. Immunostains for CK7, CD10, and RCC antigen are not shown.