摘要目的：探讨结直肠无蒂锯齿状腺瘤/息肉（ SSA/P ）的临床病理特征及其鉴别诊断。方法对同济大学附属同济医院2008至2013年间5209例结直肠内镜活检标本进行回顾性阅片，筛选出353例锯齿状病变纳入此次研究范围；收集和分析相关临床病理资料，观察SSA/P镜下病理形态特征以及与其他亚型之间的鉴别诊断要点，评价其活检组织的诊断标准。结果353例结直肠锯齿状病变中检出SSA/P 25例（7.1％），增生性息肉（ HP ）278例（78.8％），传统锯齿状腺瘤（ TSA ）44例（12.5％）。25例SSA/P中男16例，女9例，平均年龄62.2岁（34～84岁）；发生部位依次为乙状结肠14例，升结肠9例，直肠1例及横结肠1例。内镜描述肿瘤多为宽蒂息肉。活检标本病灶直径0.3～2.0 cm（平均直径0.73 cm）。光镜观察，典型SSA/P显示明显的锯齿状结构和隐窝结构的异常；隐窝扩张、隐窝分支在SSA/P和HP两组中的检出率分别是：100％（25/25）和24％（12/50，P＜0.01）；72％（18/25）和4％（2/50，P＜0.01）；“L”形/锚状隐窝、黏膜肌的假浸润、细胞核的不典型性和黏液分泌增多仅在SSA/P中发现，检出率分别为48％（12/25）、16％（4/25）、32％（8/25）和24％（6/25）。结论结直肠SSA/P的组织形态学特点是明显的锯齿状结构和隐窝结构的异常，内镜取材的完整性和正确的石蜡块包埋方向（纵向包埋）有利于诊断和鉴别诊断；不伴异型增生的SSA/P需与HP相鉴别，尤其是病变较小、仅表现为少数隐窝异常者。

abstractsObjective To investigate clinicopathological characteristics of colorectal sessile serrated adenoma/polyp ( SSA/P) and its differential diagnosis from other serrated lesions. Methods Clinicopathological features of all cases of colorectal serrated lesions from 5 209 colorectal biopsy samples at Shanghai Tongji Hospital from 2008 to 2013 were reviewed.Three hundred and fifty-three cases of serrated lesions were erolled in the study .Morphological features of SSA/P were investigated with an emphasis on histologic criteria for diagnosis and a literature review was performed.Results Three hundred and fifty-three cases of serrated lesions were identified , including 25 SSA/P ( 7.1%) , 278 hyperplastic polyp ( HP, 78.8%) , and 44 traditional serrated adenoma ( TSA, 12.5%).Twenty-five patients with SSA/P consisted of 16 males and 9 females with a mean age of 62.2 years ( aged 34-84 years ) and the lesions involved sigmoid colon (14 cases), ascending colon (9 cases), rectum (1 case) and transverse colon (1 case).Grossly, the majority of SSA/P was sessile with an averaged size of 0.73 cm.Histologically, typical SSA/P had elongated crypts with prominent serration and distorted crypts architecture.The detection rates of crypts dilatation and branching in SSA/P and HP were 100% ( 25/25 ) and 24% ( 12/50, P <0.01 ) , 72%(18/25) and 4%(2/50, P<0.01), respectively.Morphological features observed only in SSA/P included L-shaped crypts ( 48%, 12/25 ) , pseudo infiltration of mucosa muscle ( 16%, 4/25 ) , atypical nuclei&nbsp;(32%, 8/25), and increased mucus secretion (24%, 6/25).Conclusions SSA/P microscopically shows prominent serration and abnormal architectures of crypts.Complete tissue sectioning and correct embedding are helpful for the diagnosis.SSA/P without cytological dysplasia should be distinguished from HP, especially those with only a few distorted crypts .