Published online Nov 14, 2016. doi: 10.3748/wjg.v22.i42.9400
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
Processing time: 118 Days and 19.5 Hours
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.