case_images: PMC11825228_01
case_images: Ultrasound of the right breast, 13 cm from the nipple, with 0.4 cm mass
case_images: cureus-0017-00000077429-i01.jpg
case_images: PMC11825228_01_cureus-0017-00000077429-i01.jpg
case_images: FIG1
case_images: A follow-up diagnostic mammogram with tomosynthesis revealed a 0.4 cm lesion (Figure 1).
case_images: Breast biopsy showing tufts of epithelial cells without fibrovascular cores (micropapillae) with mildly pleomorphic nuclei and prominent nucleoli (A, H&E 200x). Immunohistochemical staining revealed that the malignant cells are negative for breast markers, including GATA-3 (B, H&E 100x), ER, and TRPS1, while positive for TTF-1 (C, H&E 100x) and CK7, highly suggestive of the pulmonary origin of the tumor
case_images: cureus-0017-00000077429-i02.jpg
case_images: PMC11825228_01_cureus-0017-00000077429-i02.jpg
case_images: FIG2
case_images: Immunohistochemical analysis was positive for cytokeratin (CK) 7 and thyroid transcription factor 1 (TTF-1) and negative for GATA-3, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth receptor (HER) 2, paired-box gene (Pax) 8, and tumor protein 63 (p63) (Figure 2).
case_images: Positron emission tomography-computed tomography scan showing 2.9 x 2.4 x 2.8 cm FDG-avid right upper lung mass (SUV max 5.6)
case_images: cureus-0017-00000077429-i03.jpg
case_images: PMC11825228_01_cureus-0017-00000077429-i03.jpg
case_images: FIG3
case_images: Positron emission tomography-computed tomography (PET-CT) revealed a 2.9 x 2.4 x 2.8 cm fluorodeoxyglucose (FDG)-avid right upper lung mass (maximum standardized uptake value (SUVmax) 5.6) (Figure 3), multiple pulmonary nodules, and extensive osseous lesions throughout the axial and appendicular skeleton (SUVmax 4.9).