Aim: To investigate the incidence and localizations of lymphoid follicles (LFs) in early colorectal neoplasms in human beings.
Methods: From July 1992 to September 1999, a total of 1,324 early colorectal neoplasms were removed endoscopically or surgically at our hospital; 1,031 (77.9%) were available for analysis in this study. Localization of LFs was defined histologically: as submucosal LFs, if located under the muscularis mucosa; and as intramucosal LFs, if located across or over the muscularis mucosa.
Results: Histologically, the materials included 903 intramucosal neoplasms and 128 submucosal cancers. Overall incidence of LFs was 27.2% (280/1 031). The incidence of LFs was significantly higher in females (33.6% vs 24.9%, P=0.0064), the right-sided colon (32.2% vs 25.6%, P=0.0403) and in flat or depressed type lesions (34.6% vs 25.2%, P<0.0001) as compared to males, left-sided colon and protruding type lesions, respectively. The incidences of intramucosal neoplasms and submucosal cancers were 24.3% and 43.8%, respectively (P<0.0001). Localizations of LFs (intramucosal LF/submucosal LF) in depressed, flat, and protruding types were 1/24, 14/36, and 131/74, respectively.
Conclusion: The incidence of LFs in early human colorectal neoplasms significantly differs by gender, location, macroscopic type, and histology. Moreover, localization significantly differs by macroscopic type.