Her-2 Discordance Between Primer and Metastasis in Atypical Presentation of Metastatic Breast Cancer at the Time of Diagnosis: A Case Report B reast cancer (BC) is the most common female cancer, the second most common cause of cancer death in women, and the main cause of death in women ages 40–59. [1] About 1–5% of the patients already show distant metastases at the time of diagnosis. The most common sites of BC metastases are liver, lung and bones. [2–4] Metastatic carcinoma of the uterus usually originates from other genital sites, most commonly being from the ovaries. [5, 6] In general, breast and gastrointestinal cancers are the most frequent extragenital tumours metastasising to the lower genital tract. [7, 8] Uterine metastasis of breast cancer has been previously reported to occur in 2–15% of patients, and invasive lobular carcinoma (ILC) is the most common histopathologic type to metastasize to the uterus. [9–12] If the uterus would be infltrated, abnormal uterine bleeding is usually the most common manifestation. [13] However, most of the uterine metastases are found on autopsy. [14] Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) are the most important markers used in management of BC, for neoadjuvant, adjuvant and metastatic disease treatment. HER2 is amplifed in approximately 20-25% of BC. HER2 amplifcation has been associated with tumor invasive, progressive regional and distant metastases, and poor prognosis in BC. [15, 16] In routine clinical practice, management of patients with metastatic BC is frequently based on the biomarker characteristics of the primary Breast cancer (BC) is the most common female cancer, the second most common cause of cancer death in women, and the main cause of death in women ages 40–59.The most common sites of BC metastases are liver, lung and bones. Metastases to the female genital tract from extragenital cancers are rare. Breasts and the gastrointestinal tract are the most common sites of the primary tumor.Several studies have carried out retrospective analyses comparing the ER, PR, and HER2 status of primary tumors and paired metastasis.We reported that HER2 discordance between primary and metastatic lesion in a 70-years old, postmenopausal woman who was diagnosed as invasive ductal carcinoma (IDC) with bone and endometrial metastases at the time of diagnosis. Keywords: Breast cancer, Her2 discordance, metastasis Irem Oner, 1 Erdem Sen, 1 Gonca Kara Gedik, 2 Burcu Keles, 3 Ceylan Ugurluoglu, 3 Ozlem Ata 1 1 Department of Medical Oncology, Selcuk University Faculty of Medicine, Konya, Turkey 2 Department of Nuclear Medicine, Selcuk University Faculty of Medicine, Konya, Turkey 3 Department of Pathology, Selcuk University Faculty of Medicine, Konya, Turkey Abstract DOI: 10.14744/ejmo.2019.48509 EJMO 2019;3(3):231-235 Case Report Cite This Article: Oner I, Sen E, Kara Gedik G, Keles B, Ugurluoglu C, Ata O. Her-2 Discordance Between Primer and Metastasis in Atypical Presentation of Metastatic Breast Cancer at the Time of Diagnosis: A Case Report. EJMO 2019;3(3):231-235. Address for correspondence: Erdem Sen, MD. Selcuk Universitesi Tip Fakultesi, Tibbi Onkoloji Anabilim Dali, Konya, Turkey Phone: +90 506 661 97 90 E-mail: dr17erdem@mynet.com Submitted Date: April 09, 2019 Accepted Date: July 01, 2019 Available Online Date: July 27, 2019 © Copyright 2019 by Eurasian Journal of Medicine and Oncology - Available online at www.ejmo.org OPEN ACCESS This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.