A rare practice case — a diminutive sessile serrated adenoma of the colon

Abstract

Aim. An illustration of a case of diminutive sessile serrated adenoma (SSA) as a variant of the development of the normal colon mucosa.Materials and methods. In 2017 a diminutive SSA was identified in the case of a 77 year-old patient. During endoscopic examination, which included white light endoscopy examination, narrow band imaging (NBI) and near focus, the main endoscopic signs of SSA were determined. Endoscopic removal of the lesion with subsequent confirmation of its histological structure was performed.Results. The colonoscopy revealed a diminutive SSA of up to 3mm in size with typical endoscopic signs: a flat-elevated type 0-IIA, a “mucinous cap”, the same color to the surrounding mucosa, pit pattern type II-О, absence of meshed capillary vessels, but with isolated dilated capillaries. Histological examination revealed the crypts to have a cytoplasmic-type serration, drop-like expansion and horizontal growth of the basal parts, without epithelial dysplasia.Conclusion. The presented clinical case shows a rare observation of a diminutive SSA, and the complexity of endoscopic diagnosis due to its small size. The above observation demonstrates one of the pathways — developing directly from the normal mucosa, bypassing the stage of hyperplastic polyp. Thus indicating the need for further study of serrated polyps, morphogenesis mechanisms and precancerous potential.