Background and Objectives: Acute appendicitis is a common surgical emergency. Incidental discovery of appendiceal neoplasms during appendectomy, while rare, carries significant clinical implications. This study aimed to determine the prevalence of such incidental neoplasms in patients undergoing appendectomy for acute appendicitis at a university hospital in Brazil. Methods: We conducted a retrospective observational study of 106 patients who underwent appendectomy for acute appendicitis at the Clementino Fraga Filho University Hospital (HUCFF) between 2014 and 2023. Clinical and histopathological data were collected from electronic medical records. Results: Incidental appendiceal neoplasms were found in 2.83% (3/106) of patients. These included neuroendocrine tumors (n=1) and low-grade mucinous neoplasms (n=2). The mean age of patients with neoplasms was 54.67 years, with a female predominance (2/3). One patient with a neoplasm died postoperatively; one of the remaining two required a subsequent right hemicolectomy. Conclusions: Histopathological examination of all appendectomy specimens is crucial for identifying incidental appendiceal neoplasms. The prevalence in our institution (2.83%) was higher than some literature reports, potentially reflecting our patient population characteristics. Standardized record-keeping is essential, and further research could refine management strategies for these conditions. Keywords: acute appendicitis, appendectomy, incidental appendiceal neoplasm, neuroendocrine tumor, mucinous neoplasm.