Sa1328 Analysis of the Human Biliary Microbiome and Its Alterations in Biliary Tract Diseases

Abstract

Background Adenomyomatosis of gallbladder (GB) is considered as benign condition, but several reports suggest association with malignancies, especially for segmental subtype. Because of this chance, patients suspected to have segmental or diffuse type adenomyomatosis on the imaging study may undergo cholecystectomy. But, in some cases, histopathology reveals only chronic inflammation. In this study, we aimed to analyze radiologic and pathologic features of chronic cholecystitis and adenomyomatosis for more accurate diagnosis. Methods Patients who performed cholecystectomy during recent four years in one medical center were reviewed retrospectively. Among those, patients who were suspected to have adenomyomatosis on their abdominal imaging but with no adenomyoma detected on the histopathologic examination were analyzed for their radiologic, pathologic and clinical features compared to patients who had consistent results between abdominal imaging and histopathologic examination. Results Among 3144 patients who underwent cholecystectomy, 358 patients were suspected to have GB adenomyomatosis on the abdominal imaging study. Among them (358 patients), only 92 patients had histopathologic findings compatible with adenomyomatosis. Remaining 266 patients (74.3%) did not have adenomyomatosis. Instead, many GB specimens showed chronic cholecystitis. In this group, diffuse subtype of adenomyomatosis was significantly frequent compared to 92 patients who had coherent adenomyoma finding for both imaging study and pathology. The frequency of accompanying GB stones was significantly higher in mismatching group. Radiologically, contour of GB wall thickening, intralesional cystic area and inner layer enhancement pattern was helpful in differentiating adenomyomatosis from chronic cholecystitis. Conclusion Chronic cholecystitis mimicking adenomyomatosis is difficult to diagnose solely based on the abdominal imaging, and this can lead to unnecessary cholecystectomy. Existence of gallstones and several radiologic features can help differentiate these challenging entities.