Case Report
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World Journal of Clinical Cases. Nov 16, 2017; 5(11): 397-402
Published online Nov 16, 2017. doi: 10.12998/wjcc.v5.i11.397
Case of gastric neuroendocrine carcinoma showing an interesting tumorigenic pathway
Noriyuki Uesugi, Ryo Sugimoto, Makoto Eizuka, Yasuko Fujita, Mitsumasa Osakabe, Keisuke Koeda, Takashi Kosaka, Shunichi Yanai, Kazuyuki Ishida, Akira Sasaki, Takayuki Matsumoto, Tamotsu Sugai
Noriyuki Uesugi, Ryo Sugimoto, Makoto Eizuka, Yasuko Fujita, Mitsumasa Osakabe, Kazuyuki Ishida, Tamotsu Sugai, Department of Diagnostic Molecular Pathology, School of Medicine, Iwate Medical University, Morioka 020-8505, Japan
Keisuke Koeda, Akira Sasaki, Department of Surgery, School of Medicine, Iwate Medical University, Morioka 020-8505, Japan
Takashi Kosaka, Shunichi Yanai, Takayuki Matsumoto, Division of Gastroenterology, Department of Internal Medicine, School of Medicine, Iwate Medical University, Morioka 020-8505, Japan
Author contributions: Uesugi N, Sugimoto R, Eizuka M, Fujita Y, Osakabe M, Ishida K and Sugai T designed the study; Koeda K, Sasaki A, Kosaka T, Yanai S and Matsumoto T collected the patients’ clinical data; Uesugi N and Sugai T analyzed the data and wrote the paper.
Informed consent statement: The patient and his family has provided permission to publish these features of his case, and the identity of the patient has been protected.
Conflict-of-interest statement: The authors declare that there are no conflicts of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Tamotsu Sugai, MD, Professor, Department of Molecular Diagnostic Pathology, Iwate Medical University, 19-1, Morioka 020-8505, Japan. tsugai@iwate-med.ac.jp
Telephone: +81-19-6515111 Fax: +81-19-6291436
Received: May 31, 2017
Peer-review started: June 3, 2017
First decision: June 27, 2017
Revised: July 13, 2017
Accepted: September 12, 2017
Article in press: September 13, 2017
Published online: November 16, 2017
Processing time: 170 Days and 5.6 Hours
Abstract

Here, we report a case of gastric neuroendocrine carcinoma showing an interesting tumorigenic pathway. A 57-year-old Japanese woman presented with epigastric tenderness, and distal gastrectomy was performed. In the surgical specimen, histologically, the tumor tissue was composed of three subtypes of tumor components showing different histological architecture and cellular atypia, diagnosed as neuroendocrine tumor (NET) G2, NET G3, and neuroendocrine carcinoma (NEC) components. Immunohistochemically, the Ki-67-positive rates of NET G2, NET G3, and NEC components were 6.5%, 99.5% and 88.1%, respectively. Although allelic imbalance (AI) on chromosomes 1p, 3p, 8q, TP53, 18q and 22q was commonly found in all components, AI of 4p was found in NET G3 and NEC components (but not in the NET G2 component). In contrast, AIs of 5q and 9p were found in only the NEC component. Thus, we showed the progression from NET G2 to NEC, via NET G3, within the same tumor.

Keywords: Stomach; Neuroendocrine tumor G2; Neuroendocrine tumor G3; Neuroendocrine carcinoma

Core tip: Gastric neuroendocrine carcninoma (NEC) is typically generated by dedifferentiation of adenocarcinoma cells to endocrine cells. However, we experienced a case of gastric NEC possibly generated from the neuroendocrine tumor (NET) component. The present case demonstrated an unconventional carcinogenic pathway in neuroendocrine tumorigenesis. In addition, we analyzed allelic imbalance in NET and NEC components and provided important insights into neuroendocrine carcinogenesis.