One potential harm of nonoperative management for acute appendicitis is missed appendiceal cancer, a rare and often aggressive malignancy due to the frequency of late stage of diagnosis. Previous studies have reported an increasing incidence of appendiceal neoplasms in the population. This is a retrospective case-control study of 1007 adult patients, who presented to the University of North Carolina-Memorial Hospital (UNC-MH) between 2011 and 2015 with clinical signs and symptoms of appendicitis. We evaluated the incidence of primary appendiceal cancer in this population and determined factors that predict appendiceal cancer diagnosis using multivariate logistic regression analysis. The overall incidence of appendiceal neoplasm for adult patients presenting to UNC-MH with appendicitis from 2011 to 2015 was 2.3 per cent (23/1007). The incidence in patients without appendiceal perforation on pathology was 1.9 per cent (16/832). Age (odds ratio (OR) 1.03), number of days of abdominal pain (OR 1.16), self-reported fever (OR 2.08), appendiceal width (OR 1.95), and appendiceal wall thickness (OR 1.30) were predictors of appendiceal neoplasm diagnosis in patients that present with acute appendicitis. We recommend that an operative approach to acute appendicitis should remain the standard of care because operative management may not only be diagnostic but potentially therapeutic.