Diagnosis of colorectal tumorous lesions by magnifying endoscopy,☆☆,,★★

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Abstract

Background: The magnifying colonoscope allows 100-fold magnified viewing of the colonic surface. Methods: We examined 2050 colorectal tumorous lesions by magnifying endoscopy, stereomicroscopy, and histopathology and classified these lesions according to pit pattern. Based on stereomicroscopy, lesions with a type 1 or 2 pit pattern were nontumors, whereas lesions with types 3s, 3L, 4, and/or 5 pit patterns were neoplastic tumors. Results: The pit patterns observed by magnifying endoscopy were fundamentally similar to those demonstrated in stereomicroscopic images. When the diagnosis by magnifying endoscopy was compared with the stereomicroscopic diagnosis, there was agreement in 1130 of 1387 lesions (81.5%). True neoplasms could be differentiated from non-neoplastic lesions. Of lesions with a type 5 pit pattern with a bounded surface, 11 of 22 (50%) were found to be invasive cancers with involvement of the submucosal layer. If this pit pattern is found to involve a relatively broad area of the mucosal surface, extensive malignant invasion (sm-massive) should be strongly suspected. Conclusions: The magnifying colonoscope provides an accurate instantaneous assessment of the histology of colorectal tumorous lesions. This may help in decision making during colonoscopy. (Gastrointest Endosc 1996;44:8-14.)

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PATIENTS AND METHODS

From February 1990 to June 1994, we examined 2050 colorectal lesions by magnifying endoscopy, stereomicroscopy, and standard histopathology. Lesions were histopathologically classified into three types: tubular adenoma (n = 1381), villous adenoma (n = 64), and early colorectal cancer (n = 168). The majority of these tumorous lesions were located in the rectosigmoid (47.5%), followed in number by the transverse colon (23.6%), ascending colon and cecum (19.4%), and the descending colon (9.6%). Of

Comparison of observations of pit pattern by magnifying endoscopy and stereomicroscopy

During the study period we examined 1387 of the colorectal tumorous lesions by both magnifying endoscopy and stereomicroscopy (Table 1). The images of pit patterns obtained by magnifying endoscopy were fundamentally similar to those provided by the stereomicroscope, although the former were occasionally difficult to evaluate because of the problems with staining outlined above and because of the dynamic nature of magnifying observation. At 100× magnification, the actual field of view and focal

DISCUSSION

Recent progress in endoscopic diagnosis has greatly improved the diagnosis of early colorectal cancer. It is most notable that minute cancers are now identified, among them types IIc, IIc + IIa, and IIa + IIc, i.e., depressed type cancers, that previously were not recognized. Cancers of the depressed type, which are small but have a proclivity for submucosal invasion, are very important in the developmental process of colorectal cancer.1, 2 Depressed type cancers, often detectable by their

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From the Department of Gastroenterology, Akita Red Cross Hospital, Akita, and the First Department of Pathology, Niigata University School of Medicine, Niigata, Japan.

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This work was supported by a grant in aid for cancer research from the Ministry of Public Welfare of Japan.

Reprint requests: Shin-ei Kudo MD, PhD, Gastroenterology, Akita Red Cross Hospital, 1-4-36 Nakadori, Akita-shi, Akita 010, Japan.

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