The authors describe a case of acute appendicitis associated to the histological finding of a “serrated” adenoma (SA). SA is a colorectal pre-cancerous lesion which presents the morphological and architectural characteristics of hyperplasic polyps, combined with aspects of adenomatous dysplasia. SA can eventually evolve into a malignant cancer, similarly to classic adenomatous polyps. Clinical and pathological aspects of this lesion are hereby analysed, with respect to recent Literature data.