case_images: PMC9899908_01
case_images: Radiology. (A) Left craniocaudal (LCC) view and (B) left mediolateral oblique (LMLO) view of mammography. (C) Representative ultrasound imaging of a breast lesion. (D) Representative MRI imaging of a breast lesion.
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case_images: The mammography and ultrasonography revealed an irregular, bulky mass with a lobulated border in the lateral part of the left breast ( Figures 1A-C ). On MRI, there was a 3-cm mass in the lateral part of the left breast with a high signal intensity at the periphery of the tumor ( Figure 1D ). The diagnosis and treatment timeline are demonstrated in  Supplementary Figure S1 .
case_images: Histology: (A) x25 magnification, (B) x50 magnification, and (C) x100 magnification of H&E staining for representative osteoid matrix and necrosis. (D) Immunohistochemistry (IHC) staining of SATB in representative tumor areas. (E) IHC staining of AE1/3 in representative tumor areas.
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case_images: Osteoid matrix and necrosis were frequently seen at the periphery of the tumor ( Figures 2A-C ). The following immunohistochemistry (IHC) results were obtained: Cytokeratin AE1/AE3 (AE1/AE3) (-), cluster of differentiation 56 (CD56) (focal+), special AT-rich sequence-binding protein (SATB) (+), murine double minute2 (MDM2) (+), smooth muscle actin (SMA) (partial+), Ki-67 (80%), cytokeratin 7 (CK7) (-), estrogen receptor (ER) (-), progesterone receptor (PR) (-), human epidermal growth factor receptor 2 (Her2) (0), cluster of differentiation 34 (CD34) (-), and S-100 (-) ( Figures 2D, E ).