| Theme | "Laterally spreading tumor" of the large intestine | |
|---|---|---|
| Title | About "laterally spreading tumor" | |
| Publish Date | 1998/09 | |
| Author | Shin-ei Kudo | Division of Gastroenterology, Akita Rcd Cross Hospital |
| [ Summary ] | We suggest that lesions consisting of tumors with a cluster of granules are likely to extend laterally, rather than vertically, when their size exceeds 10mm in a diameter and should be LST(laterally spreading tumor). We have noted that there are also tumors which extend laterally but are not of the granular type, non-granular type, flat elevated type or the pseudo depressed type. The developmental process of small flat elevated tumors is roughly divided into two types ; the protruding type and the LST type. The protruding types are those with a IIIL- 1 pit pattern, consisting only of the long tubular type. The LST type desplays a IIIL-2 pit pattern which consisting normal round pit surrounded by a tubular pit. We investigated frequency of submucosal invasion in 428 lesions of LST. The frequency of submucosal invasion of the homogeneous type was very low(0.7%). Nodular-mixed types exceeding 20 mm in a diameter, were strongly indicative of submucosal cancer. The rate of submucosal cancer of the flat elevated type was 6.3%. This was especially, so in the pseudo-depressed type, which exceeding 20 mm(46%). They have a high likelihood of becoming submucosal cancer. The granular type has showen mostly IIIL-1 and IV pit patterns. On the other hand, the non-granular type has showen a mostly IIIL-2 or V pit pattrnm. It is rarely found in IV pit pattems and does not show the tendency to be of the protruding type of the pseudo-depressed type. Therefore a relationship has been suggested to depressed type of early colorectal cancer. The pseudo-depressed type of non-granular LSTs has a high malignancy potential. It has been shown to have a great significance in the developmental progression of colorectal cancer. |
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