Objective  To study the clinicopathologic features of mixed neuroendocrine-non-neuroendocrine neoplasms (MiNEN).

  Methods  The medical records of 7 MiNEN cases were collected. The histopathological morphology was observed, the histopathological and immunohistochemical were labeled, and the clinicopathologic features and prognosis were analyzed.

  Results  Among 7 cases, there were 5 males and 2 females, aged 48 to 83 years. The neoplasm of 1 case located in esophagus, 3 in stomach, 1 in duodenum, 1 in rectum, and 1 in pancreas. Microscopy showed that the tumor of esophagus was squamous cell carcinoma and neuroendocrine tumor(NET G3). Non-neuroendocrine tumors of stomach, duodenum, rectum were adenocarcinoma, and their neuroendocrine tumors were small cell carcinoma (3 cases), large cell carcinoma (1 case), and NET G3 (1 case), and tumors of pancreas showed it belonged to ductal carcinoma and neuroendocrine tumor(NET G1). Non-neuroendocrine tumors (squamous cell carcinoma or adenocarcinoma) showed positive epithelium by immunohistochemical staining; there were 7 cases with positive CKpan and Syn of neuroendocrine tumor, 6 cases of positive CD56 and 1 case of negative CD56. The percentage of patients with positive Ki67 protein was 1%to 80%. Three of seven cases had lymph node metastasis. The follow up lasted for 3 to 33 months. During follow-up, 5 patients were alive and 2 died.

  Conclusion  MiNEN is an uncommon neoplasm. Correct diagnosis is important for clinical treatment and prognosis.