| [ Summary ] |
Disease entity "non-granular type laterally spreading tumor (LST-NG)" was described by Kudo in 1993. Recently some LST-NG type lesions, which were difficult to distinguish from IIc type, have been reported. The aim of this study is to clarify clinicopathological and molecular characteristics, which differentiate between IIc and LST-NG type lesions. A total of 156 IIc type lesions and 130 LST-NG lesions resected surgically or endoscopically at NCCH and HCCHE, were included in this study. We investigated some clinical, pathological (height of tumor, up-ward growth, non-neoplastic gland, and budding) and molecular (K-ras and P53) characteristics. Both IIc and LST-NG lesions were detected in significant numbers in males rather than females (p<O.O1). The incidence of LST-NG in the rectum/right side colon was higher than that seen in the left side colon. The incidence of submucosal (sm) invasive carcinoma of IIc and LST-NG was 52% and 29%, respectively. The height (height of tumor / height of normal mucosa) of IIc, LST-NG and protruded type was 0.9 +/- 0.3, 1.4 +/- 0.5 and 3.5 +/- 1.3 respectively. Histological findings of upward growth and non-neoplastic glands were observed in approximately 70-80% of LST-NG type lesions. However, branching glands were observed infrequently in both IIc and LST-NG lesions. Lymphoid follicle formation in the submucosa was observed in 34% of IIc and 44% of LST-NG type lesions. Genetically, K-ras codon12 mutation was seen infrequently in either IIc or LST-NG type lesions. P53 overexpression (diffuse pattern) was observed in approximately 50% of IIc and LST-NG type lesions. These results suggested that LST-NG type lesions are not similar to IIc type from the clinicopathological view points, but genetically, LST-NG type lesions have character istics similar to IIc type lesions. There are border line lesions, so-called "pseudo-depressed type of LST-NG", categorized between IIc type and LST-NG type lesions. |