Challenges and predictive radiological findings in the diagnosis of neuroendocrine tumors in patients with acute appendicitis.

Abstract

Background: Acute appendicitis is one of the most common surgical emergencies. With antibiotic-first treatment strategies gaining importance, the risk of an appendiceal tumor as an incidental finding or as the cause of appendicitis presents an obstacle to a conservative approach. Neuroendocrine tumors, the most frequent type of appendiceal tumors, are difficult to diagnose preopera-tively due to their small size. This study aims to identify predictive factors for neuroendocrine tumors in patients undergoing surgery for acute appendicitis by analyzing imaging and clinical characteristics, thereby enhancing preoperative diagnostic accuracy and guiding surgical interventions.

Methods: This retrospective observational study included 1,298 patients who underwent appendectomy from January 2014 to May 2024. After excluding 59 patients with normal pathology results, 40 with variable pathologies, and 49 with inaccessible computed tomography (CT) images, 1,150 patients remained (1,135 with acute appendicitis and 15 with neuroendocrine tumors). Abdominal CT scans were evaluated for appendiceal diameter, wall thickness, cecal wall thickness, periappendiceal fat stranding, fluid collection, lymphadenopathy, intraluminal and free periappendiceal air, mucosal hyperenhancement, the presence of appendicolith, mural calcification, and mural nodules.

Results: The presence of a mural nodule protruding into the lumen was significantly higher in neuroendocrine tumor patients compared to those with acute appendicitis, with a sensitivity of 53.3%, specificity of 95.8%, positive predictive value (PPV) of 31.9%, negative predictive value (NPV) of 99.4%, and accuracy of 97.9%. Intraluminal air was also more frequent in neuroendocrine tumor patients, with a sensitivity of 53.3%, specificity of 76.7%, PPV of 2.9%, NPV of 99.2%, and accuracy of 76.4%. Other imaging parameters did not show significant differences between the two groups.

Conclusion: This study identifies mural nodules and intraluminal air as significant predictors of neuroendocrine tumors in patients with acute appendicitis, emphasizing the importance of meticulous preoperative imaging evaluations. Incorporating these predictors into diagnostic protocols could improve the preoperative identification of neuroendocrine tumors, enabling more appropriate surgical interventions. Future research should validate these findings through prospective studies and explore advanced imaging techniques to further enhance the detection of appendiceal neoplasms, ultimately improving patient outcomes and reducing overlooked malignancies.