Immune–Inflammatory Markers Associated With Occult Appendiceal Neoplasms in Patients With Acute Appendicitis

BackgroundAcute appendicitis ranges from mild inflammation to perforation. A clinically important subset of cases harbors an occult appendiceal neoplasm that is often indistinguishable from routine appendicitis preoperatively. Blood-derived inflammatory indices have been proposed as predictors of disease severity and malignancy. We evaluated the diagnostic value of platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), and CRP/SII for predicting complicated appendicitis and identifying neoplasms.MethodsWe conducted a 5-year retrospective study of 837 appendectomies at a tertiary surgical center. Preoperative clinical, laboratory, imaging, and histopathologic findings were analyzed. Appendicitis severity was classified according to WSES criteria. Diagnostic performance was assessed using logistic regression and receiver-operating characteristic (ROC) analysis.ResultsAppendiceal neoplasms were found in 1.1% of patients and were uniformly unsuspected intraoperatively. Neoplastic patients were significantly older (P P P = 0.005). PLR (AUC 0.868) and SII (AUC 0.770) showed the strongest discrimination between benign and malignant pathology. CRP/SII showed the best performance for complicated appendicitis (AUC 0.703). Age, PLR, and CRP/SII were independent predictors of neoplasm, while SII, PLR, and CRP/SII were independently associated with complicated disease.DiscussionAppendiceal neoplasms may present as clinically uncomplicated appendicitis. Simple inflammatory indices-particularly PLR and SII-were associated with both disease severity and hidden malignancy. These inexpensive and widely available markers may support early surgical decision-making in older or high-risk patients. Prospective validation is needed to define optimal thresholds and refine their role in preoperative triage.