PMC7204778_01
Computed tomography (CT) images. a A new, 14-mm mass appeared adjacent to the Roux-en-Y limb without invasion into the small bowel (22 months ago; circle: tumor). b The tumor increased in size to 33 mm 6 months ago (circle: tumor). c-e Preoperative CT showed a heterogeneously enhanced tumor with a diameter of 82 x 75 mm by axial (c) and coronal imaging (d, e) (arrows: anastomotic site; circle: tumor).
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F1
The mass had increased in size from 33 mm (6 months before) to 82 mm at the time of the operation (Fig. 1).
Positron emission tomography (PET) images. The tumor (circle) showed a heterogeneously enhanced uptake on the lesion (SUVmax = 4.40) in the pelvis. No significant findings indicating metastasis or any other lesions were observed. a Whole body scan. b, c Axial images.
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F2
Apart from this, there were no significant findings that indicated metastasis or any other lesions (Fig. 2).
Macroscopic findings in the resected specimen. a The resected specimen was a solid lesion with no necrosis or bleeding, measuring 10 x 9 x 8 cm. b, c No exposure to the mucosa of the adjacent small intestine was observed, indicating its origin in the mesentery of the small intestine.
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F3
Macroscopically, the resected specimen was a 10 x 9 x 8 cm-sized solid lesion with no necrosis or bleeding (Fig. 3).
Histopathology of the resected specimen. a, b Spindle-shaped cells resembling fibroblasts or myofibroblasts proliferated sparsely with intervening collagen fibers. c Invasive proliferation into the surrounding fat tissue was observed in the marginal area of the tumor (arrow). There was no continuity between the tumor (on the left side) and the wall of the small intestine (on the right side). d-i The immunohistochemistry results showed positivity for nuclear accumulation of beta-catenin (d, e), and negativity for alpha-smooth muscle actin (f), CD34 (g), desmin (h), and c-kit (i).
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F4
Invasive proliferation into the surrounding fat tissue was observed in the marginal area of the tumor (Fig. 4). Moreover, positivity for the nuclear accumulation of beta-catenin was observed (Fig. 4).