Primary coexisting adenocarcinoma of the colon and neuroendocrine tumor of the duodenum: A case report and review of the literature

Figure 3 Gastroscopy and endoscopic ultrasonography. A: Gastroscopy findings of the mass; B: A slightly hypoechoic lesion with a broad base and approximately 8.9 mm × 6.3 mm is seen in the mucosal layer of the anterior wall of the duodenum (orange triangles).