Efficacy of Magnifying Colonoscopy for the Diagnosis of Colorectal Neoplasia: Comparison With Histopathological Findings

Background: Some authors have reported a good correlation between the shape and arrangement in the orifice of mucosal crypt (pit pattern) in the diagnosis of colorectal lesions and histopathological findings. However, there remains no good consensus on the definition of irregularity in configurations. Methods: We studied 110 colorectal neoplasia of 110 cases that were examined using a magnifying colonoscope and resected endoscopically or surgically between 2001 and 2003. We divided the lesions into two groups according to Fujii's classification as follows: type Non‐V showed type III or IV by Kudo's classification and irregular pits not occurring in a demarcated area; and type V showed irregular pits, which occurred in a demarcated area in addition to type V N by Kudo. The diagnosis by this classification correlated with the histopathological findings. We also addressed the causes of misdiagnosis in comparison with histopathological findings. Results: The diagnostic accuracy for Non‐V and V was 95.1% and 82.1%, respectively. Lesions classified as V showed a significant correlation. Histologically, carcinoma consisted of high‐grade atypia ( P < 0.0001), an erosive change of surface epithelium ( P < 0.0001) and the appearance of desmoplastic reactions ( P = 0.002) in comparison with Non‐V. Misdiagnosis was likely due to differences in the grade of atypia between superficial and deeper glands and explainable erosive changes on the surface, as well as simple misreading of the pit pattern. Conclusion: Diagnosis of colorectal neoplasia by magnifying colonoscope using our classification was useful for evaluating the depth of invasion and correlated well with histopathological findings.