PMC5658651_01
Endoscopic view of a submucosal tumor in the rectum.
CG-CGCR170086F001.jpg
PMC5658651_01_CG-CGCR170086F001.jpg
F1
Colonoscopy revealed a submucosal tumor with slightly erythematous surface in the rectum (Figure 1).
Endoscopic ultrasonography showing a homogeneous hypoechoic lesion and continuity between the tumor and the muscularis layer (arrow).
CG-CGCR170086F002.jpg
PMC5658651_01_CG-CGCR170086F002.jpg
F2
Continuity between the tumor and the muscularis layer was suggested (Figure 2).
Hematoxylin and eosin staining of spindle-shaped cells with hyalinized fibrocollagenous tissue accompanied by psammomatous calcification and multifocal lymphoplasmacytic infiltrate (magnification 100x).
CG-CGCR170086F003.jpg
PMC5658651_01_CG-CGCR170086F003.jpg
F3
The tumor located in the muscularis layer consisted of spindle-shaped cells with hyalinized fibrocollagenous tissue accompanied by psammomatous calcification and multifocal lymphoplasmacytic infiltrate (Figure 3).
alpha-SMA staining of focally positive spindle-shaped cells (magnification 400x).
CG-CGCR170086F004.jpg
PMC5658651_01_CG-CGCR170086F004.jpg
F4
Immunohistochemistry showed that the spindle-shaped cells were focally positive for alpha-SMA (Figure 4), whereas they were negative for CD34, S100, c-kit, and DOG1.