Histology of original invasive (A-B) and recurrent (C-F) breast carcinoma. H & E stained section showing invasive ductal carcinoma, grade 3 from 2005. (B) The carcinoma was positive for estrogen receptor (ER) and progesterone receptor (PR), and negative for Her2. (C) The recurrent small cell carcinoma from 2012 is characterized by spindle cells with frequent mitosis and single cell necrosis. (D-F) The recurrent carcinoma is focally positive for mammoglobin (MG), PR, and TTF1.