case_images: PMC7078443_01
case_images: Pre-NAC imaging examinations of the right breast tumor (Fig. 1A-G). A: Mammography showed a solitary mass with ill-defined margins, a coarse calcification, and pleomorphic calcifications (yellow arrow). B: Ultrasonography showed a solitary mass with smooth or irregular margins. C: Dynamic contrast-enhanced T1-weighted 3.0 T magnetic resonance imaging (MRI) with fat suppression (90 s) showed a 3.6-cm oval mass with partially ill-defined and markedly enhanced margins. High FDG uptake for right breast tumor (D), regional lymph node (E), supraclavicular lymph node (F), and internal mammary lymph node (G; yellow arrow) in positron emission tomography-computed tomography (PET-CT) imaging. Post-NAC imaging examinations of the right breast tumor (Fig. 1H). H: 3.0 T MRI (90 s) after receiving neoadjuvant chemotherapy showed the remaining 2.7-cm tumor with a reduction in size and decreased enhancement.
case_images: gr1.jpg
case_images: PMC7078443_01_gr1.jpg
case_images: fig0005
case_images: Mammography showed a solitary mass with ill-defined margins containing a coarse calcification with pleomorphic calcifications around it in the same area (Fig. 1A). Ultrasonography examination also showed a heterogeneous and solitary mass with smooth or irregular boarders (Fig. 1B). Contrast-enhanced 3.0 Tesla (T) magnetic resonance imaging (MRI) also showed a 3.6-cm oval mass with partially ill-defined margins and a heterogeneous internal enhancement in her right breast (Fig. 1C). Positron emission tomography-computed tomography (PET-CT) imaging demonstrated 18F-fluorodeoxyglucose (FDG) uptake (maximum standardized uptake value [SUVmax]: 7.14) by the same lesion as well as in the axillary, supraclavicular, and internal mammary LNs (Fig. 1D-G). T contrast-enhanced MRI after NAC treatment showed the remaining 2.7-cm mass with a reduction in size and decreased enhancement (Fig. 1H).
case_images: Histological and immunohistochemical findings of the tumor. A, B: Invasive ductal carcinoma detected via core needle biopsy (A: hematoxylin and eosin staining, x100; B: hematoxylin and eosin staining, x400). Immunohistochemical analysis of the tumor showed absence of estrogen receptor (C) and human epidermal growth factor receptor-2 (D). E: Well-developed terminal duct lobular unit-like structures in the core needle biopsy specimens (hematoxylin and eosin staining, x100). F: A well-demarcated, solid mass which suggests organoid type FA (hematoxylin and eosin staining, scanning magnification). G: Fibroadenoma with fibrous scar (yellow loop), which was considered as post therapeutic effect (hematoxylin and eosin staining, x20). H: Fibrous scar in the tumor (hematoxylin and eosin staining, x200).
case_images: gr2.jpg
case_images: PMC7078443_01_gr2.jpg
case_images: fig0010
case_images: The tumor was pathologically diagnosed as invasive ductal carcinoma (IDC) using core needle biopsy (CNB), which was histological grade 3 (Fig. 2A, B). No expression of estrogen receptor (ER), progesterone receptor (PgR), or human epidermal growth factor receptor-2 (HER2) was observed, indicating a triple negative phenotype (Fig. 2C: Expression of ER, Fig. 2D: Expression of HER2). Technologies, Tokyo, Japan) labeling index was 75.8%. The parenchyma of the CNB specimen was surrounded by a dense population of well-developed terminal duct lobular unit-like structures (Fig. 2E). The pathological examination on operative specimens revealed a well-demarcated, solid mass macroscopically (Fig. 2F). Additionally, we found the dense fibrous stroma in the FA without any residual viable invasive tumor cells (Fig. 2G). FA, and no scar was found in the adjacent breast parenchyma (Fig. 2H). Fibrous scar tissue was also detected in one of the axillary LNs, but no viable tumor cells were found.