case_images: PMC11824813_01
case_images: Diagnostic mammogram with craniocaudal view of the left breast showed a smoothly marginated isodense mass measuring approximately 3 cm in the upper outer left breast directly underneath the triangular marker placed over the region of the palpable lump. The breast is comprised of scattered areas of fibroglandular density.
case_images: CRIRA2025-9943282.001.jpg
case_images: PMC11824813_01_CRIRA2025-9943282.001.jpg
case_images: fig1
case_images: Bilateral digital diagnostic mammogram with breast tomosynthesis was performed and showed a smoothly marginated isodense mass measuring about 3 cm in the upper outer quadrant of the left breast (Figure 1).
case_images: Targeted ultrasound of the left upper outer breast mass demonstrated a smoothly marginated hypoechoic mass 8 cm from the nipple and measuring 2.8 x 1.6 x 2.8 cm with internal and marked color Doppler vascular flow.
case_images: CRIRA2025-9943282.002.jpg
case_images: PMC11824813_01_CRIRA2025-9943282.002.jpg
case_images: fig2
case_images: The patient then underwent a targeted breast ultrasound, which confirmed the presence of a 2.8 x 1.6 x 2.8 cm smoothly marginated parallel hypoechoic vascular mass in the upper outer left breast located in the 2:00 position, 8 cm from the nipple (Figure 2).
case_images: Ultrasound-guided biopsy of the mass in the left upper outer quadrant was performed. The above image shows the biopsy device with a needle tip in the mass.
case_images: CRIRA2025-9943282.003.jpg
case_images: PMC11824813_01_CRIRA2025-9943282.003.jpg
case_images: fig3
case_images: The finding was assigned the category of 4 according to the Breast Imaging Reporting and Data System (BI-RADS), and ultrasound-guided biopsy was recommended and subsequently performed (Figure 3).
case_images: (a) Low-power view demonstrating a solid stromal neoplasm with tumor cells arranged around dilated and branching vasculature (H and E stain, 40x magnification). (b) High-power view showing haphazardly arranged spindle to ovoid cells without significant atypia. Mitoses were evident (arrow) but did not exceed three mitoses per high-powered field (H and E stain, 400x magnification). (c) Immunohistochemistry stain for STAT6 demonstrating strong positivity in tumor cells. AE1/3, desmin, S100 protein, CD31, and ERG were also performed and negative. This phenotype confirms the diagnosis of solitary fibrous tumor (immunohistochemistry stain, 200x magnification).
case_images: CRIRA2025-9943282.004.jpg
case_images: PMC11824813_01_CRIRA2025-9943282.004.jpg
case_images: fig4
case_images: Histopathologic findings of the specimen demonstrated spindled to ovoid cells with indistinct cell borders arranged haphazardly around branching and dilated vasculature within the variably collagenous stroma (Figures 4(a) and 4(b)). Immunohistochemistry (IHC) was performed and the tumor cells were positive for STAT6 (Figure 4(c)) and negative for AE1/3, desmin, S100 protein, CD31, and ERG.