| [ Summary ] |
Recent Japanese studies have disclosed that sessileprotruded (Is type) cancers with submucosal invasion consist of two different types considering the origin and growth pattern. One is cancer with polypoid growth (PG). Another is that with nonpolypoid growth. We devided 32 lesions of Is type cancers with submucosal invasion (sm cancers) into PG type, NPG type and mixed type. Pathologic and endoscopic findings between PG and NPG type sm cancers were comparatively analyzed. The NPG type ratio of sm cancer was 25.0%. The average size of NPG type sm cancers was ll.6mm in maximum diameter, while that of PG type was 19.9 mm. According to 823 lesions of surgically and endoscopically resected materials between 1995 to 1997, the frequency of sm cancers of all NPG type sessile polyps was high (63.6%) while that of all PG type sessile polyps was very low (2.2%). There is a high probability of invasion into the submucosa despite the smaller size as compared with PG type tumors. Therefore, it is very important for the endoscopist to promptly find NPG type tumors during actual colonoscopy. Colonoscopic features of NPG type sm cancer were as follows (1) The base of the protrusion is covered with normal mucosa, usually appearing white. (2) It shows stiffness or a solid sensation. (3) The tumor surface is smooth or amorphous with dyespraying. (4) There is a so-called IIc like irregular margin on the border of cancer and normal mucosa is seen. |