A.R.) sought in 1995, histologic guidance and training on sporadic flat colonic adenomas by Dr Tetsuichiro Muto, Tokyo University, Japan. Subsequently, one of the authors reviewed all sporadic flat adenomas filed at Muto’s Department8 and later examined all sporadic flat adenomas filed at other hospitals in the Tokyo area.9, 10 and 11 A total of 1014 flat colorectal lesions were reviewed in Tokyo, which Everolimus order were compared with 600 lesions in Sweden. Those studies

revealed that sporadic flat (nonpolypoid) adenomas were more advanced (in terms of high-grade dysplasia [HGD]) and more aggressive (in terms of intramucosal and submucosal invasion) in Japan than in Sweden. Although the causes for the difference in those disparate geographic regions remains debatable, the findings helped us to understand some of the unclear

points and discussions that appeared in the literature on this subject. In 1996, Jaramillo and colleagues3 detected at endoscopy 104 small polyps in 38 of 85 Swedish patients with UC: 74% were endoscopically flat, 23% polypoid (20% sessile and 3% pedunculated), and in 3% the endoscopic appearance was not recorded. The pathologic examination revealed nonpolypoid (flat) adenomas in 14%, tubular or villous structures with dysplastic cells in the lower part of the crypts in 5%, nonpolypoid hyperplastic polyps in 34%, mucosa with inflammation in 7%, and mucosa in remission in 40%. Data show that nonpolypoid adenomatous lesions are commonly found in IBD colectomy specimens with carcinoma. One of the authors has previously reviewed 96 colectomy specimens with C646 UC and carcinoma filed at the Department of Pathology, St Mark’s Hospital, London, UK (Fig. 1). A total of 3049 sections were available in the 96 colectomy specimens; the mean number of sections/colectomy studied was 31.8 (range 7–97 sections).1 In addition to carcinomas, several circumscribed adenomatous

lesions were found elsewhere in the colon or rectum; they will be referred Chlormezanone to as synchronous adenomatous lesions (SALs). Using a low-power examination (4x), the histologic profile of these circumscribed lesions was classified into polypoid and nonpolypoid, both in areas with UC and in areas without inflammation. A total of 104 SALs were found in the 96 colectomies: 73 SALs, which occurred in areas with inflammation, and 31 SALs, in areas without inflammation. Polypoid SALs were recorded in 35% (n = 34) of the 96 colectomies. Polypoid SALs in areas with inflammation exhibited irregular dysplastic glands with a jigsaw pattern having irregular bands in the interspersed lamina propria. The mucosa adjacent to these adenomatous lesions showed irregular, dysplastic crypts. Polypoid SALs were found in 47% (n = 34) of the 73 SALs occurring in areas with inflammation. Polypoid SALs in areas without inflammation had a more regular glandular pattern and the interspersed lamina propria was more regularly distributed, and the adjacent mucosa showed no dysplasia.