Pit pattern diagnosis of early colorectal carcinoma by magnifying colonoscopy: clinical and histological implications

The relation between subclassification of V type pit pattern and histopathologic features, particularly, in regards to the invasion depth, was examined in 75 cases of early colorectal carcinoma. After we classified two grades (VA, VN) of V type pit pattern, we subclassified VN type pit pattern into three subtypes (Grade A, B, and C) according to the degree of appearance of VN pit pattern. V type pit pattern subclassification was diagnosed with use of a magnifying colonoscope. There were 37 VA type lesions, 8 VN.Grade A type, 16 VN.Grade B type, and 14 VN.Grade C type lesions. The incidence of submucosal massive invasion (sm2, sm3) rates was 5 (14%) of the 37 VA type lesions, 3 (38%) of the 8 VN.Grade A type, 15 (94%) of the 16 VN.Grade B type and 14 (100%) of the 14 VN.Grade C type lesions, respectively. The incidence of desmoplastic reaction (++) levels in VN.Grade B and C type lesions was significantly higher than that in VA type lesions (P<0.01), and that in VN.Grade C type lesions was significantly higher than that in VN.Grade A type lesions (P<0.05). The incidence of pit disorder or destruction (+) and (++) levels in VN.Grade B and C type lesions was significantly higher than that in VA type lesions (P<0.01), and that in VN.Grade C type lesions was significantly higher than that in VN.Grade A type lesions (P<0.01). The incidence of high grade carcinoma in VN.Grade B and C type lesions was significantly higher than that in VA type lesions (P<0.01), and that in VN.Grade C type lesions was significantly higher than that in VN.Grade A type lesions (P<0.05). These findings indicate that V type pit pattern subclassification, including our new subtype, is useful for predicting the detail invasion depth of early colorectal carcinoma. These V pit pattern subtypes are based on the degrees of desmoplastic reaction, pit disorder or destruction, and histologic grade of carcinoma.