| 特集名 | 大腸IIc -- 未来に向けて | |
|---|---|---|
| 題名 | 大腸IIcの特徴 (2) 病理形態学的特徴 b. 大腸癌の発育進展におけるIIcの意義と悪性度について | |
| 発刊年月 | 2008年 11月 | |
| 著者 | 味岡 洋一 | 新潟大学大学院医歯学総合研究科分子・診断病理学分野 |
| 【 要旨 】 | 要旨はありません。 | |
| Theme | Aiming at the future of depressed type of lesion in early colorectal cancer | |
|---|---|---|
| Title | Significance of IIc in development of colorectal carcinoma and its biological behavior -- From histopathologic aspect | |
| Author | Yoichi Ajioka | Division of Molecular and Diagnostic Pathology, Graduate School of Medical and Dental Sciences, Niigata University |
| [ Summary ] | Macroscopically depressed intramucosal carcinoma (M-Ca) is classified into the absolutely depressed type and the relatively depressed type. The former are true depressed lesions while the latter are elevated lesions. The absolutely depressed type maybe considered true IIc and are characterized by de novo origins, as well as being predominantly composed of carcinomas with high grade atypia. When associated with marginal IIa lesions, neoplastic areas are confined to depressed areas only. IIa areas usually consist of resions of non-neoplastic reactive mucosa. To elucidate the significance of IIc (absolutely depressed type) as a precursor to invasive colorectal carcinoma, remnant intramucosal cancer components of submucosal carcinoma (SM-Ca) were investigated. Of those studied, 31 / 368 SM-Ca (8.4 %) showed remnant mucosal components, having similar histologic characteristics to those of absolutely depressed IIc M-Ca. From this data, it was concluded that the rate of IIc as a precursor for invasive carcinoma may be estimated to be less than 10 % . However, this 8.4 % frequency may be underestimated and the rate of IIc as a precursor for invasive carcinoma may be higher. There is a possibility that some of SM-Ca without remnant intramucosal components, comprising 33.4 % (123 / 368) of SM-Ca, may contain SM-Ca originating from absolutely depressed IIc M-Ca in which all intramucosal components were destroyed during deeper submucosal invasion. IIc is thought to have more aggressive biological behavior compared to that of other macroscopic types of tumors at the point of submucosal invasion. The size of SM-Ca which was thought to have originated from absolutely depressed IIc M-Ca tumors was smaller to those which were thought to have originated from other macroscopic type M-Ca tumors. This may explain the fact that IIc M-Ca began submucosal invasion at a smaller size than other type of M-Ca tumors. On the other hand, there were no significant differences in rates of lymphatic, or vascular or lymph node invasion, leading to metastasis (both overt metastasis and isolated tumor cell) in any SM-Ca cases, regardless of their having M-Ca precursors. This data suggests that it cannot be considered that SM-Ca originating from IIc displays more aggressive biological behavior than SM-Ca originating from other types of M-Ca. |
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