Morphological characteristics and diagnostic criteria of traditional serrated adenoma

Traditional serrated adenomas (TSAs) are extremely rare polyps from the group of serrated polyps of the colon. TSAs is no more than 5 % of all colon polyps. A relatively small number of studies have been devoted to this histological variant, at the same time, some aspects of the morphological diagnosis of TSA still remain undisclosed. Purpose: to conduct a clinical and morphological analysis of cases of TSAs.Materials and methods. The study included 57 cases of TSAs diagnosed in the period from 2021 to 2023. In the cases detected during this period, the results of histological and endoscopic studies were analyzed.Results. The age of patients ranged from 44 to 78 years and averaged 61.7 years. The ratio of men and women is 1:1.8. Most TSAs were found in the rectum (n = 28) and sigmoid colon (n = 20). In 8 cases, the tumor was localized in the descending part and the splenic flexure of the colon. In 1 observation, a tumor was found in the cecum. The sizes of the polyps ranged from 0.5 cm to 3.5 cm. In 22 cases, the composition of the polyp included tubulovillous adenomas (16 cases) and hyperplastic polyps (6 cases) in addition to TSAs. In 5 cases, foci of highly differentiated adenocarcinoma were detected in the TSAs material.Conclusion. TSAs has characteristic morphological features with a serrated exophytic growth pattern, cytoplasmic eosinophilia and the presence of ectopic crypts. Due to the difficulties of morphological diagnosis, TSAs in some cases remains undiagnosed. At the same time, due to the increased malignant potential, TSAs requires special vigilance on the part of pathologists and clinicians.