Incidentally Detected Gallbladder Carcinoma in Routine Cholecystectomy Specimens: A Retrospective Observational Study of Frequency and Histopathological Spectrum at a Tertiary-Care Teaching Hospital in North India

Abstract

Background: Gallbladder carcinoma is the most common malignancy of the biliary tract and is frequently detected only on histopathological examination of gallbladders removed for presumed benign disease. We examined the frequency, histological spectrum and clinicopathological features of incidentally detected gallbladder carcinoma at a tertiary-care teaching hospital in North India. Materials and Methods: All cholecystectomy specimens reported between 30 June 2022 and 30 May 2026 were reviewed retrospectively. Gallbladder neoplasms were identified and, where reports were retrievable, characterized for age, sex, pre-operative clinical suspicion, histological subtype, grade, tumor (pT) stage, lymphovascular and perineural invasion and margin status. Lesions carrying a documented pre-operative suspicion of malignancy were classified separately and not counted as incidental. Results: Of 964 cholecystectomies, 14 (1.5%) were flagged as gallbladder neoplasms; detailed reports were retrievable for 11. One specimen showed a benign gallbladder with a separate peritoneal adenocarcinoma and was excluded. Of the remaining ten gallbladder neoplasms, seven were invasive carcinomas and three pre-invasive; three carcinomas carried a pre-operative suspicion of malignancy and were analysed separately, leaving four incidental invasive carcinomas and three incidental pre-invasive lesions. Women predominated (nine of ten) and ages ranged from 41 to 77 years. All four incidental invasive carcinomas were tumor stage pT2, with perineural invasion in three, lymphovascular invasion in two and margin involvement in three, and spanned four different morphologies – signet-ring cell, mucinous, mucin-rich biliary-type and intestinal-type adenocarcinoma. The clinically suspected group included an adenosquamous (collision) carcinoma staged pT3N1. Conclusion: Gallbladder neoplasia was found in approximately 1.5% of routine cholecystectomies. Incidental carcinomas were uniformly pT2 rather than early, with frequent adverse pathological features, and an unusually broad range of aggressive morphologies was encountered in a small number of cases. A structured approach that includes histopathological examination of every cholecystectomy specimen, careful subtyping of any neoplasm, and prompt staging when invasive carcinoma is found is essential to avoid understaging and to guide further management.