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Gastroenterology Research and Practice
Volume 2014, Article ID 153935, 8 pages
Research Article

Histological Distinction between the Granular and Nongranular Types of Laterally Spreading Tumors of the Colorectum

1Department of Gastroenterology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan
2Department of Human Pathology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan

Received 16 June 2014; Accepted 28 July 2014; Published 11 August 2014

Academic Editor: D. Fan

Copyright © 2014 Shingo P. Goto et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Colorectal laterally spreading tumors (LSTs), which are classified into granular (LST-G) and nongranular (LST-NG) types, are a good indication for endoscopic treatment. In practice, the nongranular type is more difficult to remove endoscopically than the granular type. It might be assumed that some histological differences exist between these subtypes. The objective of this study was to analyze histological features of laterally spreading tumors and compare between the granular and the nongranular types. A total of 32 cases of LSTs resected endoscopically being intramucosal tumors with no previous treatment were analyzed. The disposition of the muscularis mucosae, the vascular density, and the degree of fibrosis of the submucosal layer were determined. The outline of the muscularis mucosae in LST-NG was almost flat, but that of LST-G was wavy. The submucosal vascular density was significantly greater in the LST-NGs (/mm2) than in the LST-Gs (/mm2; ). There was no clear difference in the degree of submucosal fibrosis between the subtypes. A flat disposition of the muscularis mucosae and a more densely vascularized submucosal layer were characteristics of LST-NGs compared to the LST-Gs. These findings may play a role when performing the endoscopic resection of LSTs.