Clinicopathological features of primary gastric neuroendocrine neoplasms: A single-center analysis

[Mixed Neuroendocrine-non-neuroendocrine Neoplasm of the Stomach that is Distributed in Depth on the Same Tumor: Inconsistent with the Definition of Mixed Adenoneuroendocrine Carcinoma in the 2010 World Health Organization Classification of Tumors of the Digestive System]

A mixed adenoneuroendocrine carcinoma (MANEC) of the stomach is a rare disease entity that was first defined by the World Health Organization (WHO) classification (2010) for tumors of the digestive system. According to the WHO classification (2010), MANEC is referred to as a tumor with both neuroendocrine and non-neuroendocrine neoplasms; each component of the tumor should be at least 30%. On the other hand, this cut-off value lacks clinical evidence and does not explain the characteristics and heterogeneity of this tumor. A 66-year-old male diagnosed with early gastric cancer (EGC) at a community hospital was referred to the Kosin University Gospel Hospital for further evaluation of gastric cancer. Esophagogastroduodenoscopy and EUS performed at the Kosin University Gospel Hospital revealed a sub-mucosal tumor-like component. In addition, a re-biopsy revealed a neuroendorine tumor at different depths of the same tumor. The final pathologic-diagnosis through surgery revealed a mixed neuroendocrine- non-neuroendocrine neoplasm, which is inconsistent with the definition of MANEC. Clinicians should consider EUS when a tumor has atypical endoscopic findings, even if EGC has already been diagnosed.

Gastric neuroendocrine tumor treated with endoscopic submucosal dissection

A case of a 59-year-old male patient with gastric neuroendocrine tumor which was misdiagnosed as adenocarcinoma, is presented. Herein, primary diagnosis was made due to the similarity of endoscopic pictures of both diseases and dues to the inappropriate interpretation of a small biopsy sample. The patient was qualified for endoscopic submucosal dissection. Microscopic examination of whole lesion, supplemented by immmunohistochemical reactions (chromogranin A, synaptophysin, cytokeratins 7 and 20, Ki67) revealed gastric neuroendocrine tumor (NET) G2.

The lesson learnt is that to provide effective treatment to the patient, it is necessary to use all available methods to make a proper diagnosis and to distinguish the suspected disease from others with similar features.