case_images: PMC11319815_01
case_images: Abdominal CT with contrast: (A) axial arterial phase; (B) axial venous phase; (C) coronal arterial phase. Contrast-enhanced CT displays a well-defined mass of 7.8 cm x 4.2 cm x 5.1 cm (arrow) originating from the small bowel with heterogeneous enhancement, distal intestinal dilatation, and pneumatosis.
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case_images: Abdominal computed tomography (CT) revealed intestinal wall thickening, mass-like alterations, and luminal narrowing, with contrast-enhanced CT (arterial phase and venous phase, respectively) showing inhomogeneous enhancement of the mass and absence of swollen lymph nodes in the abdominal cavity ( Figure 1 ).
case_images: H&E stain (A) reveals uniform small round cell; x20. Immunohistochemistry displays positive staining for CD99 (B), Fli-1 (C), CD138 (D), WT-1 (E), and Ki67 (F); x20.
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case_images: Hematoxylin and eosin (H&E) stain revealed uniformly distributed round and oval tumor cells ( Figure 2A ). Immunohistochemical analysis indicated positive staining for CD99, FLi-1, Ki-67, CD38, and WT-1 and negative for ERG ( Figures 2B-F ).
case_images: The 18F-FDG PET/CT imaging 11 months after chemotherapy revealed intense uptake in the mesentery (arrows) and peritoneum (arrowheads) around surgical anastomosis, with a SUVmax of 16.3 [(A) MIP, (B, D) CT, and (C, E) fusion].
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case_images: f3
case_images: However, 12 months post-surgery (six cycles of chemotherapy), an MRI revealed a left peritoneal lamellar shadow, corroborated by PET/CT findings indicating metabolic activity in the mesentery and left peritoneal soft tissue nodules, indicative of tumor metastasis ( Figure 3 ).