case_images: PMC10031012_01
case_images: Breast imaging. Ultrasonography shows cystic solid compound echo with a size of 56*44*27mm of the left breast.
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case_images: The breast ultrasound confirmed the presence of cystic solid compound echo, with a size of 56*44*27mm ( Figure 1 ).
case_images: Histology of breast carcinoma with choriocarcinomatous features (BCCF). Hematoxylin-eosin staining (x100): close transition from the BIDC to the choriocarcinomatous areas (A). Hematoxylin-eosin staining (x200): giant cells with prominent pleomorphic nuclei and abundant eosinophilic and vacuolated cytoplasm resembling cytotrophoblastic and syncytiotrophoblastic cells (B). Immunohistochemistry of choriocarcinoma components (x100): HCG (C), GATA3 (D), HER2 (E), KI67 (F), P53 (G) are positive; ER (H), PR (I), AR (J) are negative. Fluorescence in situ hybridization (FISH): HER-2 gene amplification (HER2/CEP17 ratio = 2.31) (K).
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case_images: Furthermore, there was a close transition from the BIDC to the choriocarcinomatous areas on several slides ( Figure 2 ). Abbott Park, IL) according to the manufacturer's instructions. According to the 2018 ASCO/CAP guidelines, the HER2 FISH results is considered Positive: HER2 gene amplification (HER2/CEP17 ratio = 2.31) ( Figure 2 ).
case_images: DNA STR analysis. DNA STR analysis reveals the genomic DNA alleles of the choriocarcinomatous differentiated components are identical to those of the BIDC components, exhibiting that the choriocarcinoma is nongestational.
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case_images: PMC10031012_01_fonc-13-984425-g003.jpg
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case_images: The results of the STR analysis are shown in  Figure 3 .