Discordence of HER-2/neu overexpression and estrogen receptor between the primary breast cancer and axillary lymph node with metastasis

20106 Background: Adjuvant hormonal therapy and trastuzumab are known to be associated with a significant reduction in cancer-related mortality in a subset of women with breast cancer. The treatment decision is usually based on immunohistochemistry (IHC) staining of the primary tumor. We reported here a case of discordance of HER-2/neu overexpression and estrogen receptor status between the primary breast cancer and axillary lymph node with metastasis. Methods: IHC and fluorescence in situ hybridization (FISH) analysis was perfromed for the assessment of HER-2/neu. E-cadherin staining was done on the primary tumor and lymph node with metastasis. Results: A 52 year old woman presented with right breast lump. The imaging studies showed a 5 × 5 cm speculated mass. No other abnormalities were noted. An excision biopsy revealed 3 cm moderately differentiated invasive lobular carcinoma. Subsequently a wider excision and axillary lymph node dissection was done. 2/20 lymph nodes were involved by the cancer. IHC w...