PMC5367864_01
The colonoscopy showed an elevated tumor with central ulceration in the rectosigmoid.
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An elevated tumor with central ulceration was found 10 cm from the anal verge by colonoscopy (Fig. 1), and biopsy specimens revealed a spindle cell tumor.
An axial view of the abdominal CT scan. A giant tumor was found in the space surrounded by the rectosigmoid segment, uterus, and right ovary.
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Abdominal CT scan revealed a 10 cm mass in the rectosigmoid that invaded the uterus (Fig. 2).
Hematoxylin-eosin staining of the tumor revealed spindle-shaped cells (original magnification: 40x).
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Routine hematoxylin and eosin staining showed proliferation of spindle-shaped tumor cells with enlarged nuclei and eosinophilic cytoplasm (Fig. 3).
Immunohistochemical staining of the tumor. (A) Desmin, (B) IA-4, (C) c-kit, and (D) DOG1 (original magnification: 40x).
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Immunohistochemically, the tumor was positive for desmin and SMA, whereas c-kit, DOG1, CD34, and S-100 protein were not expressed (Fig. 4).