Pathological Characteristics of Small Superficial Type Epithetial Neoplasia of the Large Intestine with Special Reference to Its Macroscopic Criteria Yoichi Ajioka 1 , Hidenobu Watanabe 1 , Tadasu Chida 1 1The First Department of Pathology, Niigata University School of Medicine Keyword: 大腸上皮性腫瘍 , 表面型大腸上皮性腫瘍 , 肉眼型分類 , Ⅱa型 pp.837-846
Published Date 1990/7/25
DOI https://doi.org/10.11477/mf.1403111106
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 The classification of the superficial type (flat type) neoplasias has been decided subjectively according to the gross configurations of the lesions. The macroscopic characteristics of flat-type neoplasias by our previous macroscopic classification proved to be as follows: -“Size/height≧3 and flat surface (sphericity≦1.2)”. We defined the superficial type (Ⅱa type) neoplasia as those showing the macroscopic height of more than 3 mm (proposed macroscopic classification), and we reclassified 421 epithelial neoplasias, less than 10 mm in diameter, of the large intestine.

 We made a comparison of the incidence and the malignancy rate of the superficial type neoplasias lying between the two macroscopic classifications. The incidence of f lat type adenoma less than 5 mm was 22.4%, and the incidence of Ⅱa type was 91.3%. The incidence of flat type pure carcinoma between 5 to 10 mm was 58.8%, and the (incidence of) Ⅱa type between 5 to 10 mm was 88.3%. The Flat type showed a malignancy rate not significantly different to Is and Ip type in sizes less than 5 mm, and significantly higher than Ip type in sizes between 5 to 10 mm. The Ⅱa type showed a malignancy rate significantly less than that of I type in sizes less than 5 mm, and not significantly different among those between 5 to 10 mm in size.

 From the results, we concluded that the proposed classification better explains the initial macroscopic manifestations of adenomas, and characteristics of pure carcinomas. So we proposed the macroscopic criterion of the superficial (Ⅱa type) type as those with a height of less than 3 mm.

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