A preliminary report of gastroenteropancreatic neuroendocrine tumors in one institution: CT, MRI and clinicopathological features

Objective: To present the imaging and clinicopathological features of gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Material and methods: Between January 2013 and December 2015, 48 patients with surgically diagnosed GEP-NETs ( 34 male and 14 female) underwent preoperative multidetector computed tomography or magnetic resonance imaging. The clinical and imaging features of the patients were reviewed and analyzed. Results: Pancreatic tumors are mainly located in the head and body of the pancreas. Gastrointestinal involvement included the following: 12 tumors located in the stomach, 11 in the rectum, 3 in the esophagus or colon, and 2 in the duodenum or appendix. Patients were mainly diagnosed in their 50 s to 70 s with a mean age of 61 years. The dominant clinical symptoms included abdominal pain, dysphagia, hematemesis or hematochezia and neuroendocrine-related symptoms. 20 tumors were classified as G3, 12 as G2 tumors, 11 as G1 and 5 as mixed adenoneuroendocrine carcinoma. The immunohistochemical markers chromogranin and synaptophysin were positive. The pancreatic tumor showed iso-to hypoattenuation on plain computed tomography (CT), iso-to hypointensity on T1-weighted imaging and iso-to hyperintensity on T2-weighted imaging. The enhancement pattern was variable. The CT features of GEP-NETs mainly included wall thickening, and nodules or masses on the wall of the gastrointestinal tract. The two main enhancement patterns were moderately homogeneous and irregularly heterogeneous. 14 cases of lymph node metastases, 9 of liver, 3 of lung and one of lumbar vertebrae were also detected by CT. Conclusions: in China, the most common sites for GEP-NETs are the pancreas, stomach and rectum. The imaging features of pancreatic NETs and GEP-NETs are nonspecific.