PMC5348452_01
A: plain phase. A tumor about 40 mm in diameter was found in S4/8 of the liver, most of which showed low intensity, but the dorsal area and periphery of the mass showed high intensity. B: Artery phase. The peritumoral area was slightly enhanced. C: Portal phase. The peritumoral area and dorsal area of the tumor were slightly enhanced. D: Equilibrium phase. The intratumoral septum was identified.
1349-7235-56-0289-g001.jpg
PMC5348452_01_1349-7235-56-0289-g001.jpg
g001
These high-density areas showed mild enhancement in arterial phase contrast-enhanced CT (Fig. 1).
The colonoscopy and pathological findings. A: A yellow-colored submucosal tumor 8 mm in diameter at the rectum was found. B: Biopsy showed peripheral ribbon-like tumor cells (Hematoxylin and Eosin staining, x4). C: Endoscopic ultrasonography revealed a homogeneous hypoechoic mass located within the submucosal layer.
1349-7235-56-0289-g002.jpg
PMC5348452_01_1349-7235-56-0289-g002.jpg
g002
The tumor measured 8 mm in diameter without central depression (Fig. 2A). Biopsy showed that this submucosal tumor was a well-differentiated NET (Fig. 2B). Endoscopic ultrasonography (EUS) using a miniature probe (20 MHz) with the water-filling method indicated a homogeneous hypoechoic mass, originating from the mucosa and submucosa that infiltrated within the upper two thirds of the submucosa at maximum (Fig. 2C).
The pathological findings of partial hepatectomy. A: The tumor was composed of uniform cells, arranged in cords and with a ribbon-like pattern [Hematoxylin and Eosin (H&E) staining, x40]. B: H&E staining, x200. C: The immunohistochemical findings of Ki-67 staining.
1349-7235-56-0289-g003.jpg
PMC5348452_01_1349-7235-56-0289-g003.jpg
g003
The tumor also contained a central region of necrosis, probably due to ischemia (Fig. 3A and B). The mitotic count was low, and the Ki-67 proliferation index was less than 2% (Fig. 3C).
The pathological findings of endoscopic submucosal resection with a ligation device (ESMR-L). A: Complete resection of the tumor in the submucosal layer. B: The tumor was composed of uniform cells, arranged in cords and with a ribbon-like pattern (Hematoxylin and Eosin staining, x200). C: The immunohistochemical findings of Ki-67 staining.
1349-7235-56-0289-g004.jpg
PMC5348452_01_1349-7235-56-0289-g004.jpg
g004
CD31 antibodies revealed no invasion into the vessels. Central depression was also not found in the specimen (Fig. 4A). As with the hepatic lesion, the mitotic count was low, and the Ki-67 proliferation index was less than 2% in the resected specimen (Fig. 4B and C).