Colorectal neuroendocrine carcinoma: A case report and review of the literature

Figure 1 Imaging findings. A: Contrast-enhanced computed tomography (CT) of the abdomen shows an irregularly shaped and enhanced mass (10 cm) at the right colonic flexure. White arrow indicates the tumor; B: CT showed multiple low-density tumors in the liver with no enhancement effect. Black arrows indicate the tumors; C: Colonic enema with water-soluble contrast medium (Gatrografin^®) shows an irregular shape in the lumen of colon. Black arrow indicates the stenotic and irregular lesion; D: Colonoscopy showed the mass in the right transverse colon with significant stenosis due to submucosal elevation of the tumor. Black arrow indicates the submucosal elevation; E: Colonoscopy showed the necrotic tissue in the lumen of the tumor. White arrow indicates the necrotic lesion; F: Perforation of the colon by stenting. Black arrow indicates the free-air and intratumoral air outside the stent.

Figure 2 Histological findings of the tumor. A: Hematoxylin-eosin staining showed that the tumor cells were poorly differentiated; B: Complicated with the intratumoral bleeding; C: Tumor cells underwent immunohistochemical staining for Synaptophysin. Black arrows indicate the positively stained cells; D: A high proliferative fraction of immunohistochemical staining for Ki67 staining. Black arrows indicate the positively stained cells.