Retrospective Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Nov 14, 2016; 22(42): 9400-9410
Published online Nov 14, 2016. doi: 10.3748/wjg.v22.i42.9400
Lymphovascular invasion in more than one-quarter of small rectal neuroendocrine tumors
Mi Jung Kwon, Ho Suk Kang, Jae Seung Soh, Hyun Lim, Jong Hyeok Kim, Choong Kee Park, Hye-Rim Park, Eun Sook Nam
Mi Jung Kwon, Hye-Rim Park, Department of Pathology, Hallym University Sacred Heart Hospital, Hallym University Sacred Heart Hospital, Anyang-si 431-796, South Korea
Ho Suk Kang, Jae Seung Soh, Hyun Lim, Jong Hyeok Kim, Choong Kee Park, Department of Internal Medicine, Hallym University Sacred Heart Hospital, Anyang-si 431-796, South Korea
Eun Sook Nam, Department of Pathology, Kangdong Sacred Heart Hospital, Hallym University College of Medicine, Seoul 134-701, South Korea
Author contributions: Kwon MJ evaluated pathologic findings and drafted the manuscript; Kwon MJ and Kang HS contributed equally to this work; Kang HS designed the study, analyzed the data and drafted the manuscript; Soh JS and Lim H revised the manuscript for important intellectual content; Kim JH and Park CK supervised the study; Park HR and Nam ES evaluated and supervised pathologic findings; all authors have read and approved the final version to be published.
Institutional review board statement: This study was conducted with the approval of the ethics committee of Hallym University Sacred Heart Hospital in Anyang, Korea, IRB No. 2016- I093.
Informed consent statement: Patients were not required to give informed consent to the study because only pathologic reevaluation and medical records were used in this retrospective study.
Conflict-of-interest statement: The authors declare no conflict of interest.
Data sharing statement: No additional data are available.
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:
Correspondence to: Ho Suk Kang, MD, Department of Internal Medicine, Hallym University Sacred Heart Hospital, 22, Gwanpyeong-ro 170 beon-gil, Dongan-gu, Anyang-si 431-796, South Korea.
Telephone: +82-31-3803707 Fax: +82-31-3803701
Received: July 16, 2016
Peer-review started: July 18, 2016
First decision: July 29, 2016
Revised: September 10, 2016
Accepted: October 10, 2016
Article in press: October 10, 2016
Published online: November 14, 2016
Core Tip

Core tip: The majority of rectal neuroendocrine tumors (NETs) are small (66%-80% are ≤ 1 cm in diameter) and endoscopic resection techniques have shown successful outcomes. However, lymphovascular invasions, a well-established risk factor for lymph node metastasis, are often found at endoscopically resected specimens and there are no definite guidelines about these cases. Therefore, we investigate the frequency and prognostic significance of lymphovascular invasion (LVI) in small endoscopically resected rectal NETs. We found that LVI may be present in a high percentage of small rectal NETs by two histologic methods; hematoxylin and eosin staining and ancillary immunohistochemical staining (D2-40 and Elastica van Gieson). On the other hands, LVI was not associated with lymph node metastasis or recurrence in small rectal NETs (≤ 1 cm) during a 3 year-follow up period. Although our follow-up period was short, but I'm confident in our studies will be the cornerstone of future researches about significance of LVI in small rectal NETs.