Focal Thickening at the Fundus of the Gallbladder: Computed Tomography Differentiation of Fundal Type Adenomyomatosis and Localized Chronic Cholecystitis

BACKGROUND/AIMS The objective of our study was to identify useful computed tomography (CT) findings for differentiating fundal type adenomyomatosis from localized chronic cholecystitis involving the fundus of the gallbladder. METHODS We retrospectively identified cases of 41 patients with pathologically proven adenomyomatosis (n=21) or chronic cholecystitis (n=20) who had fundal thickening of the gallbladder on preoperative abdominal CT. Analysis of the CT findings included evaluation of the thickness, contour, border, intralesional cystic area, adjacent gallbladder wall thickening, presence of inner layer enhancement, enhancement grade, enhancement pattern, and presence of stones. Statistical analyses were performed using the Mann-Whitney U test and Fisher exact test. RESULTS Oval contour, inner layer enhancement and intralesional cystic area were more frequently noted in adenomyomatosis than in chronic cholecystitis (p<0.05 for each finding). Flat contour and adjacent gallbladder wall thickening were more frequently observed in chronic cholecystitis than in adenomyomatosis. No differences between adenomyomatosis and chronic cholecystitis in terms of the thickness, enhancement grade, enhancement pattern and presence of stones were apparent. CONCLUSIONS CT may help to differentiate fundal type adenomyomatosis from localized chronic cholecystitis involving the fundus of the gallbladder.