Volume 120, Issue 7, Pages 1657-1665 (June 2001) Prevalence and distinctive biologic features of flat colorectal adenomas in a North American population  Yusuke Saitoh, Irving Waxman, A.Brian West, Nikolay K. Popnikolov, Zoran Gatalica, Jiro Watari, Takeshi Obara, Yutaka Kohgo, Pankaj J. Pasricha  Gastroenterology  Volume 120, Issue 7, Pages 1657-1665 (June 2001) DOI: 10.1053/gast.2001.24886 Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig. 1 A representative case of F&D adenoma found in this study. (A) Diminutive depressed lesion with surrounding slightly elevated normal mucosa (arrows). (B) Resected specimen showing the features of a tubular adenoma. Gastroenterology 2001 120, 1657-1665DOI: (10.1053/gast.2001.24886) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig. 2 Macroscopic subtypes of F&D tumor found in this study. F&D tumors were classified into 3 subtypes (actual endoscopic appearance of polyps found in this study, with stylized diagram above): (A) flat elevated type, composed of flat elevation without depression of the surface; (B) slightly depressed type, composed mainly of depressed surface; and (C) flat elevated with depression type, composed of an area of depressed surface surrounded by an area of elevation. Gastroenterology 2001 120, 1657-1665DOI: (10.1053/gast.2001.24886) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig. 3 F&D lesions with advanced pathology found in this study. (A) Flat elevated with depression type lesion 3 mm in size detected in the descending colon. This lesion was found after dye spraying and contained high-grade dysplasia. (B) Flat elevated lesion 10 mm in size found in the cecum. This lesion contained invasive submucosal adenocarcinoma (stage I). (C) Flat elevated with depression type lesion 12 mm in size found in the sigmoid colon. This lesion contained adenocarcinoma invasive into muscularis propria with lymph node metastasis (stage III). (D) Flat elevated lesion with depression 17 mm in size detected in the rectum. This lesion contained adenocarcinoma, invasive into the subserosa (stage II). Gastroenterology 2001 120, 1657-1665DOI: (10.1053/gast.2001.24886) Copyright © 2001 American Gastroenterological Association Terms and Conditions

Fig. 4 Microphotographs of immunohistochemical staining for tumor markers in various kinds of lesions found in this study. From left to right, the 3 columns represent specimens from normal, flat, and polypoid lesions. Each row represents immunostaining for a different antigen: (A–C) p53; (D–F) FHIT; (G–I) Ki-67; (J–L) CD95. Gastroenterology 2001 120, 1657-1665DOI: (10.1053/gast.2001.24886) Copyright © 2001 American Gastroenterological Association Terms and Conditions