Serrated Adenoma of the Appendix: A Case Report

Abstract

We report a rare case of serrated adenoma of the appendix synchronously associated with adenocarcinoma of the sigmoid colon. A 69-year-old Japanese man admitted to our hospital for a routine physical checkup and colorectal endoscope was found to have a flat-elevated tumor measuring 23×8×15 mm in size in the sigmoid colon. He was healthy until this admission, with no abdominal symptoms in the previous couple of months. A surgical sigmoidectomy with routine additional appendectomy was performed. Histopathological examination of the resected tumor revealed an intra-mucosal adenocarcinoma and tubular adenoma with severe dysplasia in the sigmoid colon. The appendix, grossly unremarkable, harbored a serrated adenoma with no evidence of invasion or malignant transformation. Serrated adenoma of the appendix is extremely rare, and only one case report could be found on MEDLINE.