PMC9578916_01
Ultrasonic examination. (a): hypoechoic nodule of the breast with a clear boundary; (b): no obvious blood flow signal in CDFI.
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Ultrasound showed a 2.1 cm x 1.3 cm mass in the lower outer quadrant of the left breast, with hypoechoic, clear boundary, and no obvious blood flow signal by color doppler flow imaging (CDFI) (Figure 1), indicating a BI-RADS grade 3 breast solid lesion. The mitotic figures were about 0-1/10HPF, and no pathological mitotic figures were seen.
The tumor was composed of spindle cells and inflammatory cells. The spindle cells were arranged in bundles or spirals. HE100x (a); HE400x (b).
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Microscopically, the mass was composed of spindle cells and formed a storiform pattern, admixing diffuse lymphocytes and the plasma cell infiltrate (Figure 2). The mitotic figures were about 0-1/10HPF, and no pathological mitotic figures were seen.
ALK positive expression in spindle tumor cells. IHC 400x. (b): the testing result of ALK by separation probes of FISH, showing ALK gene rearrangement (red and green signals were separated).
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The mitotic figures were about 0-1/10HPF, and no pathological mitotic figures were seen. Immunohistochemistry (IHC) showed that tumor cells were strong and diffusely positive for ALK (Figure 3(a)), BCL-2, vimentin, P16, and patchy/weakly positive for ER, SMA, P53, and CD34. Fluorescence in situ hybridization (FISH) revealed gene fusion of 2p23 (ALK) (Figure 3(b)).