Polypoid sporadic adenomas were found in 19% (n = 18) of the 96 colectomies and 58% (n = 18) of the 31 SALs in areas without inflammation. Nonpolypoid SALs were slightly elevated (en plateau), had discrete villous changes, 4 or were flat-flat. These lesions correspond to type 0 of The Paris endoscopic classification of superficial neoplastic lesions. Nonpolypoid SALs were found in 41% (n = 39) of the 96 colectomies: 53% (n = 39) in the 73 SALs found in areas with inflammation and sporadic adenomas in 42% (n = 13) of the 31 SALs present in areas without inflammation. Invasive carcinomas were detected in 52% (n = 38) of the 73 SALs found in areas with inflammation and sporadic adenomas

in 32% (n = 10) of the 31 SALs recorded in areas without inflammations.1 Confirmatory data have been recently collected. In a more recent survey done in Florence, Italy, out of the 39 colectomy specimens with IBD and carcinoma, Lenvatinib polypoid SALs were found in 21% (n = 4) of the 19 specimens this website with UC and in 30% (n = 6) of the 20 colectomies with CC. Nonpolypoid SALs were recorded in 11% (n = 2) of the 19 specimens with UC and in 5% (n = 1) of the 20 colectomies with CC (Rubio, Nesi, in preparation). Because of the relative scarce number of cases of nonpolypoid lesions in IBD reported

in the literature, much of the available information on their histologic classification is based on endoscopically removed flat lesions in patients without IBD. The cause of the flat lesions varies greatly. Endoscopically removed flat lesions may disclose nonpolypoid hyperplastic polyps, nonpolypoid Fenbendazole serrated polyps, nonpolypoid adenomas (tubular, villous, or serrated), or invasive carcinomas. In this regards, prior observations showed that invasive carcinomas can arise de novo – without surrounding adenomatous tissue.1 Nonpolypoid hyperplastic polyps (Fig. 2) exhibit a group of tall, straight crypts without serrations, not surpassing twice the thickness of

the surrounding mucosa. Nonpolypoid serrated polyps are classified into type 1 (Fig. 3), having epithelial serrations in the superficial aspect of the crypts, and type 2, displaying similar glands as those described for sessile serrated polyps (Fig. 4). However, because type 2 is usually an intramucosal lesion, the term sessile serrated polyp cannot be applied. Nonpolypoid adenomas (Fig. 5) denote a circumscribed cluster of abnormal crypts lined with dysplastic cells having proliferative, biochemical, and molecular aberrations; they are surrounded by nondysplastic mucosa. In well-oriented sections, nonpolypoid adenomas may appear slightly elevated, with a height not surpassing twice the thickness of the nondysplastic surrounded mucosa, or depressed. Based on the structural configuration of the crypts, these adenomas are classified into tubular, villous, or serrated. Paneth cell adenoma and fenestrated adenoma are 2 unusual phenotypes of nonpolypoid adenomas.