case_images: PMC11805839_01
case_images: Longitudinal ultrasound image of the right kidney of a 5-year-old boy with a metanephric stromal tumor sharply demarcated from the renal parenchyma (arrows in a) and evidence of multiple internal cysts. Significantly reduced perfusion in the color Doppler image (b)
case_images: 247_2025_6166_Fig1_HTML.jpg
case_images: PMC11805839_01_247_2025_6166_Fig1_HTML.jpg
case_images: Fig1
case_images: A sonogram of the abdomen was performed, which showed an inhomogeneous and, compared to the renal parenchyma, hypovascularized mass with a diameter of up to 5.3 cm and multiple internal cysts in the middle third of the right kidney (Fig. 1).
case_images: The contrast agent dynamics of the magnetic resonance images of the metanephric stromal tumor of a 5-year-old-boy shows relevant enhancement in the urographic phase only. a Dynamic axial T1-weighted volumetric interpolated breath-hold examination golden-angle radial sparse parallel (VIBE GRASP) magnetic resonance image with fat saturation shows delayed contrast agent uptake of the right-sided metanephric stromal tumor in the arterial phase compared to the renal parenchyma (circle). b The dynamic contrasted axial T1-weighted VIBE-GRASP magnetic resonance image shows the right kidney including the metanephric stromal tumor in the nephrographic phase with moderate enhancement. c The dynamic contrasted axial T1-weighted VIBE GRASP magnetic resonance image shows the right kidney including the metanephric stromal tumor in the urographic phase with enhancement comparable of the renal parenchyma. d Cystic (arrow) and solid parts are well demarcated in the axial T2-weighted half Fourier-acquired single shot turbo spin echo (HASTE) sequence of the magnetic resonance imaging
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case_images: PMC11805839_01_247_2025_6166_Fig2_HTML.jpg
case_images: Fig2
case_images: T2W intermediate signal and numerous cystic internal components (Fig. 2) without contact to the renal pelvis. The contrast agent dynamics showed a clearly delayed uptake compared to the renal parenchyma with strong enhancement in the urographic phase only (Fig. 2a-c).
case_images: Axial magnetic resonance imaging of a 5-year-old boy. Absence of diffusion restriction of the metanephric stromal tumor (circles in a and b) in diffusion-weighted imaging, no apparent diffusion coefficient value reduction compared to the healthy kidney
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case_images: PMC11805839_01_247_2025_6166_Fig3_HTML.jpg
case_images: Fig3
case_images: In the diffusion-weighted imaging (DWI), the mass showed a slightly increased signal and intermediate apparent diffusion coefficient (ADC) values (mean value approx. 1.0 x 10-3 mm2/s) (Fig. 3).
case_images: Intraoperative oblique contrast-enhanced ultrasound examination of the right kidney of a 5-year-old boy with reduced contrast agent uptake of the tumor tissue (arrows) compared to the healthy renal parenchyma (asterisks) in both the early (a and b) and late (c and d) contrast phase. a, c Contrast-enhanced sonographies. b, d Grayscale sonographies
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case_images: PMC11805839_01_247_2025_6166_Fig4_HTML.jpg
case_images: Fig4
case_images: Sixteen weeks after the initial presentation of the patient, the tumor was successfully resected in total with renal preservation with help of intraoperative visualization of tumor margins by contrast-enhanced ultrasonography (CEUS) (Fig. 4).