SONOGRAPHIC DIAGNOSIS OF UNSUSPECTED GALLBLADDER CANCER - IMAGING FINDINGS IN COMPARISON WITH BENIGN GALLBLADDER CONDITIONS

OBJECTIVE. Several sonographic findings were analyzed to determine the ir significance in distinguishing gallbladder cancer from benign condi tions of the gallbladder. The analyzed findings were gallstone number and size; floating stones; displaced stones; wall thickening, irregula rity, and echogenicity; mucosal plaque; intraluminal mass; gallbladder -replacing mass; invasive gallbladder mass; gallbladder mucosal discon tinuity; hyperechoic gallbladder mucosa; and submucosal or transmural echolucency. MATERIALS AND METHODS. Sonograms of 20 patients with unsu spected, pathologically proven gallbladder cancer and 65 patients with benign gallbladder conditions (predominantly acute or chronic cholecy stitis) were retrospectively assessed by two observers who were unawar e of experimental conditions. Gallstone number and size were assessed, and the presence of floating stone (neither settling nor wall-adheren t), displaced stone (lifted from the gallbladder wall by mass or focal wall thickening), wall irregularity, mucosal plaque, intracystic mass , and gallbladder-replacing or invasive mass was evaluated. The echoge nicity pattern of the gallbladder wall was characterized, and its thic kness was measured and classified as normal/ mildly thickened (<7 mm) or moderately/severely thickened (greater than or equal to 7 mm). In a ddition, the gallbladder wail was evaluated for discontinuous mucosal echo, hyperechoic mucosa, submucosal or mural echolucency, and pericho lecystic fluid collection. Sonographic findings were compared by the M ann-Whitney test for nonparametric variables and by Student's t test f or continuous variables. RESULTS. Solitary gallstone, displaced stone, intraluminal mass, gallbladder-replacing or invasive mass, and discon tinuity of the mucosal echo were all statistically significantly more common in patients with gallbladder cancer (.001 < p <.05). Mucosal pl aque and wall irregularity were nonspecific findings. Gallbladder wall thickening by itself was nonspecific, although associated echolayerin g, transmural or submucosal edema, or a distinctly specular mucosal li ning favored benign etiologies. CONCLUSION. Several sonographic findin gs were significantly more common in patients with gallbladder cancer compared with patients with benign gallbladder conditions. Assessment of these signs may be helpful in distinguishing gallbladder cancer fro m benign conditions of the gallbladder.