PMC8204013_01
(A-D) images represent RCC and RMLO views before the first fibroadenoma surgery and in the current presentation (the inflammatory myofibroblastic tumor), respectively. Mammography obtained before fibroadenoma surgery showed (A, B) an oval-shaped, circumscribed mass and mammography performed two years after the operation showed (C, D) a slight hyperdense mass with an ill-defined, spiculated margin, accompanied by an incomplete halo sign (arrow) and thickened the skin adjacent to the areolar in the inner upper quadrant of the right breast.
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Mammography obtained before fibroadenoma surgery showed a well-defined high-density mass in the inner upper quadrant of the right breast ( Figures 1A, B ). Mammography, performed two years after the initial operation, showed a high density, irregular mass with spiculated margins, accompanied by an incomplete halo sign ( Figures 1C  arrow,  D ) in the inner upper quadrant of the right breast.
(A-F) MRI obtained two years after the operation revealed a circumscribed mass with irregular shape and slightly distorted structure, accompanied by thickening of adjacent skin in the inner upper quadrant of the right breast, a mass showed heterogeneous high signal intensity on fat-suppressed T2-weighted images and low signal intensity on T1-weighted images (A, B). The lesion with high signal intensity on DWI (C) had low signal intensity on ADC map (D), which indicated restricted diffusion. Dynamic contrast-enhanced MRI revealed a fast, heterogeneous enhanced mass in the initial phase (E). Maximum intensity projection (MIP) revealed a mass with increased blood supply (F).
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MRI of the breast performed during a prior hospital admission, including traditional MRI and gadolinium-enhanced breast MRI, revealed an irregular mass, accompanied by architectural distortion, measuring 4.5 x 3.5 x 3.0 cm in size under the scar area of the inner upper quadrant of the right breast ( Figure 2 ). DWI (b = 1000 s/mm2) with low signal intensity ADC map ( Figures 2C, D ) that suggested restricted diffusion. Dynamic-contrast enhanced MRI showed a rapid heterogeneous rim enhancement mass with dark internal septation ( Figure 2E , arrow), accompanied by non-mass enhancement in the initial period ( Figure 2E ), increased blood flow around the lesion in the maximal intensity projection ( Figure 2F ), and 201% of the early enhanced rate and a plateau in the delayed period and in the time intensity curve of the lesion ( Figure 3 ).
A time intensity curve of the mass showed a plateau (TIC II) in the delayed period.
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DWI (b = 1000 s/mm2) with low signal intensity ADC map ( Figures 2C, D ) that suggested restricted diffusion. Dynamic-contrast enhanced MRI showed a rapid heterogeneous rim enhancement mass with dark internal septation ( Figure 2E , arrow), accompanied by non-mass enhancement in the initial period ( Figure 2E ), increased blood flow around the lesion in the maximal intensity projection ( Figure 2F ), and 201% of the early enhanced rate and a plateau in the delayed period and in the time intensity curve of the lesion ( Figure 3 ).
(A-D) Histologic, immunohistochemical staining of inflammatory myofibroblastic tumor (IMT). The mass showed spindle cells admixed with inflammatory cells (H&E stain, x 100) (A). Immunohistochemical staining showed positive staining for smooth muscle actin (SMA) in the spindle tumor cells (SMA, x 200) (B), positive staining for Ki-67 in about 30% of the spindle tumor cells (Ki-67, x 200) (C), as well as positive staining for vimentin in the spindle tumor cells (vimentin, x 200) (D).
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Pathologic analysis of the mass showed proliferating spindle cells interwoven within inflammatory cells, including plasma cells and lymphocytes ( Figure 4A ). On immunohistochemical examination ( Figure 4 ), the mass was positive for smooth muscle actin (SMA) ( Figure 4B ), vimentin ( Figure 4D ), and Ki-67 in about 30% of the spindle tumor cells ( Figure 4C ) while negative for CD34.
Fluorescence in situ hybridization analysis showing no ALK gene rearrangement (x 100).
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Meanwhile, no ALK gene rearrangement was detected by fluorescence in situ hybridization ( Figure 5 ).