case_images: PMC11002110_01
case_images: (A) Ultrasound showed that there was a hypoechoic mass of about 2.6x1.8cm in the upper part of the bladder. (B) CDFI showed dot linear blood flow signals at the edge of the mass. (C) Ultrasound showed no obvious abnormalities in the bladder.
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case_images: The US revealed the presence of a hypoechoic mass measuring approximately 26mm x 18mm in the upper aspect of the bladder ( Figure 1A ). Color Doppler flow imaging (CDFI) revealed dot linear blood flow signals at the edge of the mass ( Figure 1B ), supporting the diagnosis of an urachal mass. Regular follow-up examinations over a period of three and a half years revealed no recurrence or metastasis ( Figures 1C ,  2I-K ).
case_images: Pelvic magnetic resonance and CT images. (A, B) Axial T1-weighted images showed a hypointense mass. (C, D) Sagittal T2-weighted images demonstrated a heterogeneously hyperintense mass anterior to the bladder roof, with spot-line hypointense (arrows) in the mass. (E, F) Axial T2-weighted images with fat suppression showed similar imaging findings to T2WI, the mass still showing heterogeneously hyperintense with linear and punctate hypointense (arrows). (G) Axial T1-weighted enhanced image showed obvious ring enhancement of the mass. (H) Axial DWI showed limited diffusion of the mass. (I) An Axial CT scan showed that there was no thickening or mass shadow of the bladder wall. sagittal T2-weighted image (J) and Axial T1-weighted images (K) showed that the bladder was full, and there was no obvious abnormal signal in the bladder cavity.
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case_images: Magnetic resonance imaging (MRI) depicted an irregular mass located anterior to the bladder roof near the midline ( Figures 2A-H ), measuring approximately 24 mm x 24 mm x 25 mm in dimensions (left and right diameter x anteroposterior diameter x upper and lower diameter). Regular follow-up examinations over a period of three and a half years revealed no recurrence or metastasis ( Figures 1C ,  2I-K ).
case_images: The microscopic view showed that the tumor cells were spindle-shaped (A). Immunohistochemical stains showed that HMB45 (B, C), and SMA (D, E) were positive, and Melan-A (F) was negative.
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case_images: Microscopic analysis revealed spindle-shaped tumor cells ( Figure 3A ) displaying infiltrative growth patterns with areas of necrosis. The immunohistochemical staining results indicated negative expression of AE1/AE3, EMA, S-100, desmin, ALK, SOX-10, caldesmon, and Melan-A ( Figure 3F ), while positive expression was observed for SMA ( Figures 3D, E ), calponin, CD34, HMB45 ( Figures 3B, C ), and Ki-67, with a Ki-67 positive rate of approximately 5%.