Chronic irradiation enteritis: its correlation with the elapsed time interval and morphological changes

Twenty-one lesions from 19 patients with chronic irradiation enteritis (CIE) were examined to elucidate correlations with the histological findings and either the elapsed time interval or the macroscopic features. The lesions were divided into the early CIE group (E group; the lesions resected within 2 years after irradiation) of 10 lesions and the late CIE group (L group; the lesions resected more than 8 years after irradiation) of 11 lesions. Based on the macroscopic features, the lesions of CIE were divided into three types: ulcerative stricture type (U type; 11 lesions), serosal adhesion type (A type; 6 lesions) and wall sclerosing type (S type; 4 lesions). Only A type lesions were observed in the E group, and U type lesions were significantly more frequently encountered in the L group (9 of 11; 82%) than in the E group (2 of 10; 20%). Moderately to markedly degenerated changes of the vessel wall (8 of 11; 73%), enteritis cystica profunda (8 of 11; 73%), atypical epithelia (7 of 11; 64%), and the occurrence of fistula (2 of 11; 18%) were all significantly more frequently present in the L group than in the E group. No radiation-induced colorectal carcinomas were observed. The authors thus conclude that CIE is a slowly progressive disease. The late CIE showed macroscopically ulcerative stricture type properties with tissue degradation, such as fistulas, perforation, and dysplastic epithelia compared with early CIE; thus, long-standing CIE should be followed for the early identification of further complications. The classification of CIE based on macroscopic features is, therefore, considered to be useful to understand the clinical course of this disease better.