Ultrastructure of colon pit pattern classification / 中华消化内镜杂志

ABSTRACT

Objective To explore morphological changes in evolution of colorectal pit patterns and their relation with polyp development by observing the uhrastructure of colorectal polyps. Methods Analy-ses were based on data from 50 subjects with colorectal polyps diagnosed with magnifying colonoseopy. Colonoscopy comb/ned with endoscopic lesions staining was employed to determine the pit pattern of colorec-tal 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 pattern of 50 samples included 10 cases of type Ⅰ , 8 eases of type Ⅱ, 15 eases of type Ⅲ, 9 cases of type Ⅳ, 5 cases of type Ⅴ and 3 eases 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%, re-spectively. 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 increasing-ly atypical hyperplasia in the epithelial eells and heterotypic tissues. Transmission electron microscopy re-veahd epithelium of type Ⅰ and type Ⅱ ananged 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 ⅣV and type Ⅴ was char-acterized by sparse and irregular villi, swelling mitechondria and expanded endoplasmic reticuhm, lysosomes of increased number, heterotypic nuclear and mitotic nuclear, and broken and disappearing substrate. Con-dusion Morphological changes in pit pattern of colorectal polyps is affected by sudaee structure of glandular epithelial cells, the proportion and composition of the crypt surface cellsn. Ultrastrnetural changes in epithe-lial cells are the material basis of morphological changes in pit pattern and polyp development.