case_images: PMC8602786_01
case_images: (A) Ultrasonographic image showing a low echo mass in the upper inner quadrant of the left breast and with an irregular shape and uneven internal echogenicity. (B, C) Color-flow Doppler image showing small amount of blood flow signals inside and vessels in rim. (D) No enlarged lymph nodes were found in the armpit.
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case_images: The right breast and both axillary regions showed no evidence of disease ( Figure 1 ).
case_images: (A-C) Axial and sagittal contrast-enhanced MR image shows rapid and heterogeneous tumor enhancement. (D) Dynamic contrast-enhanced magnetic resonance imaging (MRI) demonstrated a time-signal intensity curve (TIC) with a rapid rise to a peak (after the administration of the contrast material), followed by a slow-out at the mass.
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case_images: In addition, left axillary lymphadenopathy with preserved fatty hilum and regular cortex was observed in this patient ( Figure 2 ).
case_images: Histopathology of primary tumor. (A) Hematoxylin and eosin staining (magnification: x100); (B) immunohistochemistry for CD68 (magnification: x100); (C) immunohistochemistry for CD163 (magnification: x100); (D) immunohistochemistry for PR (magnification: x100); (E) immunohistochemistry for ER (magnification: x100); (F) immunohistochemistry for KI-67 (magnification: x100).
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case_images: At the same time, the patient underwent wide local excision and sentinel lymph node biopsy, which was finally diagnosed as giant cell tumor of breast soft tissue ( Figure 3A ). Microscopically, this tumor was composed of round or oval mononuclear cells and numerous osteoclast-like multinucleated giant cells ( Figure 3A ). Immunohistochemically, the tumor showed a strong positive reaction in the giant cells to the histiocytic marker CD68 ( Figure 3B ) and a positive reaction in the mononuclear component to antibodies against vimentin and CD163 ( Figure 3C ). The tumor was negative for progesterone receptor (PR) ( Figure 3D ) and estrogen receptor (ER) ( Figure 3E ), and the Ki-67 labeling index was 30% ( Figure 3F ).
case_images: Chest CT showed that a soft tissue nodule in the left upper lobe with lobulated contours, inhomogeneous density, and calcifications is visible inside, and the largest cross-sectional dimension of the mass was 1.0 cm x 1.1 cm.
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case_images: The largest cross section was approximately 1.1 cm x 1.0 cm ( Figure 4 ).
case_images: Histopathology of metastatic lesion. (A) Hematoxylin and eosin staining (magnification: x100); (B) immunohistochemistry for CD68 (magnification: x100); (C) immunohistochemistry for CD163 (magnification: x100); (D) immunohistochemistry for S-100 (magnification: x100).
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case_images: PMC8602786_01_fonc-11-638237-g005.jpg
case_images: f5
case_images: There are small necrosis and hemorrhage areas in the cell area ( Figure 5A ). Immunohistochemistry for CD68 was strongly positive in the tumor and stained the multinucleated cells more strongly than the mononuclear component ( Figure 5B ). S-100 protein ( Figures 5C, D  ). Knowledge of the patient's history of breast tumor and comparing the histology of the lung lesion with the original breast tumor helped the pathologist confirm that the lung nodule was a breast-derived metastasis. Starting on June 28, 2017, the patient received four cycles of systemic adjuvant chemotherapy (epirubicin and ifosfamide, a course of 21 days).