Incidental Gallbladder Carcinoma Detected in Routine Cholecystectomy Specimens: A Fifteen-Year Evaluation from a Tertiary Referral Center

Background/Objectives: Incidental gallbladder cancer (IGBC) is an uncommon but clinically important malignancy, typically diagnosed unexpectedly after cholecystectomy performed for benign indications. Despite its incidental nature, IGBC may present with advanced pathological features and unfavorable outcomes. This study aimed to evaluate the incidence, clinicopathological characteristics, surgical management, and prognostic factors of IGBC in a large cholecystectomy cohort from a tertiary referral center. Methods: A retrospective analysis was performed on 19,798 cholecystectomy procedures conducted between January 2010 and December 2025. Patients with a preoperative diagnosis of gallbladder cancer or incomplete clinical or pathological data were excluded. Only cases with invasive incidental gallbladder cancer (IGBC) were included, whereas dysplasia and carcinoma in situ were excluded. Demographic, clinical, surgical, pathological, and survival data were systematically collected. Results: Incidental gallbladder cancer was identified in 43 patients (0.22%). The mean age was 71.4 ± 9.9 years, and 74.4% were female. Gallstones were present in 88.4% of patients. Adenocarcinoma was the predominant histology (90.7%), and pT2 disease was the most common stage (41.9%), while 25.6% had advanced-stage tumors (pT3–T4). Median OS was 26.0 months, and median DFS was 25.5 months in non-metastatic patients. Pathological T stage was significantly associated with both OS and DFS. Advanced T stage, positive surgical margins, perineural invasion, lymphovascular invasion, and increasing tumor size were significantly associated with worse DFS. Re-resection rates were limited, mainly due to advanced age and comorbidities. Conclusion: Although incidental gallbladder cancer is rare, it leads to clinically and oncologically significant outcomes. In this study, pathological T stage emerged as a key prognostic factor influencing both overall survival and disease-free survival. In addition, perineural invasion, lymphovascular invasion, and positive surgical margins were identified as the main pathological factors adversely affecting disease-free survival.