Invasive lobular carcinoma metastasis to pancreas mimicking pancreatic signet ring cell carcinoma: A case report and systematic review of the literature.

Metastasis to the gastrointestinal tract is a rare instance in the natural history of breast cancer, usually in association with lobular histology and widespread dissemination of disease. We report the case of a 74-year-old woman with a history of invasive lobular carcinoma presenting with a pancreatic metastasis mimicking a primary pancreatic adenocarcinoma; we also present a systematic review of the relevant literature. The presentation of pancreatic metastasis in the setting of breast cancer is unspecific, and histology is of paramount importance for a correct diagnosis; surgical metastasectomy could be of some benefit in the correct clinical setting.

Concordance of immunohistochemistry for predictive and prognostic factors in breast cancer between biopsy and surgical excision: a single-centre experience and review of the literature.

PURPOSE: Accurate evaluation of breast cancer on bioptic samples is of fundamental importance to guide therapeutic decisions, especially in the neoadjuvant or metastatic setting. We aimed to assess concordance for oestrogen receptor (ER), progesterone receptor (PR), c-erbB2/HER2 and Ki-67. We also reviewed the current literature to evaluate our results in the context of the data available at present. METHODS: We included patients who underwent both biopsy and surgical resection for breast cancer at San Matteo Hospital, Pavia, Italy, between January 2014 and December 2020. ER, PR, c-erbB2, and Ki-67 immunohistochemistry concordance between biopsy and surgical specimen was evaluated. ER was further analysed to include the recently defined ER-low-positive in our analysis. RESULTS: We evaluated 923 patients. Concordance between biopsy and surgical specimen for ER, ER-low-positive, PR, c-erbB2 and Ki-67 was, respectively, 97.83, 47.8, 94.26, 68 and 86.13%. Cohen's κ for interobserver agreement was very good for ER and good for PR, c-erbB2 and Ki-67. Concordance was especially low (37%) in the c-erbB2 1 + category. CONCLUSION: Oestrogen and progesterone receptor status can be safely assessed on preoperative samples. The results of this study advise caution in interpreting biopsy results regarding ER-low-positive, c-erbB2/HER and Ki-67 results due to a still suboptimal concordance. The low concordance for c-erbB2 1 + cases underlines the importance of further training in this area, in the light of the future therapeutic perspectives.