大肠腺管开口分型的超微结构研究

Ultrastructure of colon pit pattern classification

目的通过对大肠息肉的超微结构观察，分析其表面腺管开口形态（pit pattern）的演化过程与息肉性质发生改变的关系。方法对50例大肠息肉患者行结肠放大内镜检查，结合内镜下黏膜染色对病灶行pit pattern分型，内镜或手术切除病灶，所有样本分别行组织病理学分析、扫描及透射电镜观察。结果本组50例样本，pit pattern记录Ⅰ型10个、Ⅱ型8个、Ⅲ型15个、Ⅳ型9个、Ⅴ型5个、混合型3个。组织学诊断验证其阳性预测准确率达86％（43／50），鉴别腺瘤性息肉的准确率达94％（30／32）。扫描电镜下Ⅰ、Ⅱ型隐窝规则洞状，隐窝周围细胞大小一致，吸收细胞微绒毛多，杯状细胞丰富；Ⅲ、Ⅳ、Ⅴ型隐窝逐渐变形，表面细胞及组织异型程度不断加重。透射电镜下Ⅰ、Ⅱ型腺上皮细胞排列整齐，连接紧密，腔面微绒毛规则，胞浆线粒体、内质网丰富，核卵圆形位于基底部，基底膜平滑连续；Ⅲ、Ⅳ、Ⅴ型腺上皮细胞绒毛逐渐稀疏紊乱，胞浆线粒体肿胀，内质网扩张，溶酶体数量增加，核异型、核分裂明显加重，基板逐渐出现中断或消失。结论pit pattern的变化受大肠隐窝表面细胞的形态、比例以及构成等因素的影响，腺上皮细胞的超微结构变化是pit pattern形态和息肉性质发生改变的物质基础。

Objective To explore morphological changes in evolution of colorectal pit patterns and their relation with polyp development by observing the ultrastructure of colorectal polyps. Methods Analyses were based on data from 50 subjects with colorectal polyps diagnosed with magnifying colonoscopy. Colonoscbpy combined with endoscopic lesions staining was employed to determine the pit pattern of colorectal lesions, according to Kudo classification. Colorectal lesions were removed through endoscopy or surgery. All samples were analyzed with histopathology, scanning and transmission electron microscopy. Results The pit phttern or 50 samples included 10 cases of type Ⅰ , 8 cases of type Ⅱ, 15 cases of type Ⅲ, 9 cases of type Ⅳ, 5 cases of type Ⅴ and 3 cases of mixed-type. The positive predictive rate and the accuracy rate of differential diagnosis of neoplastic polyps, verified with histological diagnosis, were 86% and 94% , respectively. Under scanning electron microscopy, crypt morphology in type Ⅰ and type Ⅱ exhibited regular round hole shape, with epithelial cells in uniform size, abundant absorptive cells with rich microvilli and goblet cells. Crypt in type Ⅲ, type Ⅳ and type Ⅴ appeared gradual deformation accompanied by increasingly atypical hyperplasia in the epithelial cells and heterotypic tissues. Transmission electron microscopy revealed epithelium of type Ⅰ and type Ⅱ arranged regularly and connected closely, with neat microvilli at the top of cells, affluent mitochondria and endoplasmic reticulum in the cytoplasm, oval nuclear at the base, and smooth and continuous basement membrane. While the epithelium of type Ⅲ, type Ⅳ and type Ⅴ was characterized by sparse and irregular villi, swelling mitochondria and expanded endoplasmic reticulum, lysosomes of increased number, heterotypic nuclear and mitotic nuclear, and broken and disappearing substrate. Conclusion Morphological changes in pit pattern of colorectal polyps is affected by surface structure of glandular epithelial cells, the proportion and composition of the crypt surface cellsn. Ultrastructural changes in epithelial cells are the material basis of morphological changes in pit pattern and polyp development.