Serrated adenocarcinoma: A new look into colorectal carcinoma in Indian population

Abstract

Context: Serrated adenocarcinoma (SAC) is a recently described, distinct variant of colorectal carcinoma (CRC), accounting for about 7.5% of all CRCs and up to 17.5% of most proximal CRCs. It arises by serrated pathway characterized by early involvement of oncogenic BRAF mutations, excess CpG island methylation and subsequent low- or high-level DNA microsatellite instability and has a poorer prognosis than conventional colorectal carcinoma. Aims: The present study is an attempt to review and reclassify colorectal carcinomas into serrated and nonserrated type, and finds its incidence and associated features. Materials and Methods: Totally, 81 histopathologically diagnosed colorectal carcinomas during the period of 2001-2008 were reviewed. Histopathological criteria by Tuppurainen et al. was used to identify SAC and its features were studied. Results: Out of the total 81 cases of colorectal carcinoma comprising of mainly adenocarcinoma (81.48%), 5 cases of SAC were identified giving an incidence of 6.17%. Female preponderance (60%) was noted with mean age of 61.8 years. Most cases were located in cecum (60%). Serrated growth pattern was most frequent, noted in 60% cases, followed by mucinous in 20% and trabecular in 20%. Serrated mucinous carcinoma case also showed the presence of papillary rods, cell balls, focal clear cell change, and intraluminal dirty necrosis. Conclusion: This study attempts to define serrated colorectal adenocarcinoma in Indian population, where it has rarely been studied, using Tuppurainen et al.′s criteria. Since it is associated with poor prognosis its recognition, it is important for appropriate follow-up and therapeutic intervention.