结直肠SSA/P和TSA的临床病理学及免疫组化研究

Clinicopathologic and immunohistochemical features of colorectal sessile serrated adenoma/polyp and traditional serrated adenoma

目的探讨广基锯齿状腺瘤/息肉(SSA/P)和传统锯齿状腺瘤(TSA)的临床病理学、免疫组化特征及癌变通路的意义。方法收集病理诊断为结直肠锯齿状病变的病例共计291例,从中筛选出结直肠锯齿状腺瘤64例(SSA/P 41例,TSA 23例),收集临床相关资料和观察镜下病理学特征,同时进行MGMT、MLH1、β-catenin、p16、CDX2、RUNX3和Ki-67免疫组化染色。选取34例增生性息肉(HP)、24例正常肠组织和28例结直肠癌(CRC)作为对照,其中HP全部为微小泡型。结果 SSA/P和TSA均好发于左侧结肠。组织学显示,SSA/P锯齿状改变腺体紧靠黏膜肌层,基底隐窝呈倒"T"或"L"型分支;TSA腺体可见明显的锯齿状结构、异位隐窝和细胞异型增生,其中纤维绒毛状TSA(FSA)异型增生程度较高。免疫组化:Ki-67、β-catenin、p16和RUNX3表达阳性率,在SSA/P和TSA组与对照组之间比较差异显著(P<0.05);MLH1表达阳性率,在SSA/P与对照组HP和正常之间差异显著(P<0.05),且阳性表达率呈递增趋势,支持广基锯齿状通路学说,提示HP是SSA/P的一种前期病变。结论 SSA/P和TSA是CRC的癌前病变,通过锯齿状通路发生恶变,具有较高恶性潜能,需要与HP加以区别。

Objective To investigate the clinicopathological features, immunohistochemieal characteristics and pathogenetic pathway of sessile serrated adenoma polyp and traditional serrated adenoma. Methods We collected 291 cases of various types of colorectal serrated lestous. From screening these cases, we found 64 cases of colorectal serrated adenomas, including 41 cases of sessile serrated adenoma/polyp （SSA/P）, 23 cases of traditional serrated adenoma （TSA）. The clinical information was collected and the microscopic pathological features observed. And immunohistochemieal staining was utilized to detect the expression of MGMT, MLH1, I^-catenin, P16, CDX2, RUNX3 and Ki-67. In addition, 34 eases of hyperplastic polyps （HP）, 24 cases of normal colon tissues and 28 cases of colorectal cancer （CRC） wereserved as controls, all of which HP was tiny bubble-type. Results SSA/P and TSA occured in the left colon, with a male predominance in SSA/P patients. Histologically, the SSA/P presented serrated change of the glands close to the muscularis mucosa, and basal crypt was inverted ＂T＂ or ＂L＂-type branching. Glands also showed visible jagged structure of TSA, ectopic crypt and cell dysplasia. Fiber villous TSA （FSA） had a higher degree of dysplasia. The expression of Ki-67, 13-catenin, p16 and RUNX3 showed significant differences between SSA/P and TSA group and control group （ P 〈 0. 05 ）. Conclusion The SSA/P and TSA are CRC precancerous lesions, and malignant transformation occurs through the serrated pathway. With high malignant potential, these need to be distinguished from HP.