ESR1 and neoplasm: Bone scan indicated sternal metastasis, chest computed tomography (CT) scan revealed the internal mammary lymph nodes (IMN) enlargement, and the core needle biopsy revealed invasive ductal carcinoma (IDC), IHC showed ER+ in 30% of tumor cells with weak staining, while PR and HER-2 showed negative, Ki67 was positive in 90% tumor cells.