臨床からみた大腸腫瘍のpit pattern診断

Pit Pattern Diagnosis of Tumors of the Colon from the Clinical Points of View

　要旨　拡大電子スコープと実体顕微鏡で観察した9,087病変のpit pattern解析を行った．従来のpit pattern分類のⅢ_L，Ⅳ，Ⅴ型を更に詳細に亜分類し，大腸腫瘍のpit patternと形態，発育進展を考察した．Ⅱa＋dep，Ⅱa，Ⅰs，Ⅰpの隆起型腫瘍のpit patternはⅢ_L，Ⅳ型が主体であり，亜分類ではⅢ_L-1A→Ⅲ_L-1B→Ⅳ_B→Ⅳvが基本的なpit patternの推移である．LSTはⅢ_L-2Aが主たるpit patternであり，Ⅱa＋dep，Ⅱaと共通する．Ⅱc，Ⅱc＋Ⅱaの表面陥凹型はⅢs，V型が主たるpit patternであり，buddingを形成しない全層性straight腺管であり，de novo発生である．Ⅴ型のamorphism（Ⅴ_A）はm癌かsm_1aであり，無構造なⅤ型（Ⅴ_N）はsm高度浸潤癌であるが，爪で引っかいたような表面構造を示すscratch signを示すⅤ_Nは主にsm₂の浸潤癌であった．pit pattern診断は古典的な内視鏡診断を変えるものであり，内視鏡レベルで腫瘍の発育進展とsm浸潤程度をより推測でき，精密な診断とより良い内視鏡治療を行うのに極めて重要である．

　The pit pattern analysis were conducted on the 9,087 lesions which were examined by magnifying electric endoscope and stereomicroscope. The Ⅲ_L, Ⅳ, Ⅴ patterns of the ordinary pit patterns classification were further classified into the sub-classification, and the pit pattern, shape and development of the colon tumor were studied. Most of the elevated lesions of type Ⅱa ＋ dep, Ⅱa, Ⅰs, Ⅰp had Ⅲ_L, Ⅳ pit patterns and the common trapition of pit pattern was described as Ⅲ_L-1A → Ⅲ_L-1B → Ⅳ_B → Ⅳv using the sub-classification. The common pit pattern of LST Ⅲ_L-2A which was similar to those of types Ⅱa ＋ dep and Ⅱa. The surface depressive lesions of types Ⅱc and Ⅱc ＋ Ⅱa had mainly Ⅱs and Ⅴ pit patterns. They were composed of transmural straight gland ducts without budding formation and they were de novo carcinomas. Amorphism of Ⅴ pattern(Ⅴ_A) was m cancer or sm_1a cancer. Although the unstructured Ⅴ pattern (Ⅴ_N) indicated sm massive invasion, Ⅴ_N pattern with scratch sign, which was compared to scratch by nails on the surface, was seen in the sm₂ invasive cancer. The pit pattern diagnosis may change classical endoscopic diagnosis, and it would predict the development of tumor and the extent of sm invasion by endoscopic examination and it is important for more precise diagnosis and better endoscopic treatment.