Abstract
In order to improve the colonoscopic diagnosis as to the depth of submucosal invasive cancer of the colorectum, we analized the clinicopathological and colonoscopic features of 42 cases of the NPG (non polypoid growth) type submucosal invasive cancer of the colorectum. The cases were categorized into 10 of sm1 (minimal submucosal invasion), 21 of sm2 (moderate submucosal invasion), and 11 of sm3 (severe submucosal invasion) according to the degree of submucosal invasion. Fourteen lesions were located in the rectum, 17 in the sigmoid colon, 5 in the descending colon, 3 in the transverse colon, and 3 in the ascending colon and the cecum. The mean±SE size of the NPG type submucosal invasive cancers was 11.6±1.6 mm in sm1, 11.9±0.8 mm in sm2 and 21.7±1.7 mm in sm3, respectively. The lesions of sm3 were significantly larger than those of sm1 and sm2 (p< 0.01). Nineteen of 21 cases of sm1 and sm3 cancers showed flat elevated lesions or distinct depressed lesions surrounded by marginal elevation, but 7 of 21 sm2 cancers showed dome-like protruded lesions in their cross-section view. Colonoscopically, the marginal elevation of the mucosa surrounding the depressed area was normal in 5 of 10 lesions of sm1, 15 of 21 lesions of sm2 and 7 of 9 lesions of sm3. White spots were found in 3 of 10 lesions of sm1, 8 of 21 lesions of sm2 and 6 of 9 lesions of sm3. Abnormal fine vessels on the cancerous mucosa were demonstrated in 4 of 10 lesions of sm1, 15 of 21 lesions of sm2 and 5 of 9 lesions of sm3. In summary, total evaluation of the findings on the size, their cross-section view (depressed, flat elevated, or dome-like protruded lesions), the elevated marginal mucosa surrounding the depressed area, white spots, and abnormal fine vessels on the cancerous mucosa gives us the exact colonoscopic diagnosis as to the degree of submucosal cancerous invasion.
