Pitfalls in diagnosing Gallbladder Carcinoma - A Single Center Histopathology Study

Background Gallbladder carcinoma is a rare cancer with incidence of less than 2 per 100,000 populations worldwide. It is the fifth most frequent gastrointestinal malignancy. Radiological or gross examination of majority of gallbladder carcinoma detects no mass. This may lead to under or over diagnosis of cases in histological examination. Objective To identify pathologic features that contribute to the difficulty in diagnosis of gallbladder carcinoma. Method Between 2018 and 2023, 22 patients with gallbladder carcinoma were identified using the histopathology registry book at the department of pathology. Blocks, slides, reports and history of those cases were retrieved and reviewed. The slides were analyzed by two or more pathologist noting some of the diagnostic difficulties which could have been encountered. The number and percentage with interpretations of the cases were noted. Result Nine of 22 primary gallbladder carcinoma cases had tumor masses. Nine cases in histological examination provided diagnostic challenges. The major pitfalls encountered while diagnosing gallbladder carcinoma was mistakenly making a diagnosis of carcinoma when only deeply penetrating Rokitansky-aschoff sinuses are present. Similarly, pathologists misdiagnose carcinoma with minimal disease as benign disease, Adenomyosis as Adenocarcinoma. Under sampling of specimen, grossly occult disease, misinterpreting extracellular mucin pools were other potential pitfalls. Conclusion Deeply penetrating Rokitansky-aschoff sinus or Adenomyosis can be mistakenly diagnosed as gallbladder carcinoma. Careful attention to any evidence of mural thickening and close examination of deeply situated glandular structures were crucial for proper diagnosis of gallbladder carcinoma.