Therapeutic Tactics for Laterally Spreading Tumor to be Based on Thorough Diagnosis Hiro-o Yamano 1 , Hiro-o Matsushita 1,2 , Kohei Kuroda 1 1Division of Gastroenterology, Akita Red Cross Hospital 2Department of Surgery, Hitoyoshi General Hospital Keyword: 側方発育型大腸腫瘍 , LST , 拡大内視鏡 , pit pattern , 早期大腸癌 pp.1759-1769
Published Date 2005/12/25
DOI https://doi.org/10.11477/mf.1403100179
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 From the viewpoint of therapeutic tactics, it is very important that we diagnose laterally spreading tumors (LST) concerning their clinicopathological characteristics. We propose that LSTs be divided into two major classes,“granular type (LST-G)” and “non-granular type (LST-NG)”. Each major class has two minor types. The former is the “homogeneous type (LST-G-H)” and the “nodular mixed type (LST-G-M)”, the latter is the “flat (LST-NG-F)” and the “pseudo-depressed (LST-NG-PD)”.

 LST-G-M and LST-NG-PD are higher than the other two types in the rate of early cancer and invasive cancer, and malignant potential depends on tumor size in all classes.

 In a study of pit pattern analysis we recognize no invasive cancer in LSTs which revealed type IIIL, and IV pit pattern. We regard them as apt for endoscopic therapy. LSTs, which revealed type VN pit pattern, are invasive cancers, and not apt for endoscopic therapy. On the other hand “type VI pit” LST included many types of pathological features, and some of them under 20mm in size showed invasive cancer, especially LST-G-M and LST-NG-PD. We feel that we should avoid making an easy decision concerning them. If we do make a resection of them, we must take fine species, which will enable us to make an accurate pathological diagnosis about the invasion of the submucosal layer and vessels clearly.

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