Sonographic features of mucus-producing carcinoma of the gallbladder

Few cases of mucus-producing carcinoma of the gallbladder have been reported; accordingly, sonographic features of this entity have not been well described. We discuss two cases of gallbladder carcinoma with marked secretion of mucus that we followed using ultrasound. Acute cholecystitis in these cases resulted from obstruction of the cystic duct by the copious secretion of mucus. Ultrasonography revealed debris-like echoes floating in the lumen of the gallbladder with buoyant migration. Mucus appeared as highly echoic smoke-like or cloud-like masses. Color flow imaging showed no vascularity. The mucus echoes disappeared spontaneously between attacks of cholecystitis. A surgical specimen showed a tumor associated with abundant mucous in the gallbladder. We conclude that mucus-producing carcinoma of the gallbladder should be considered when numerous smoke-like echoes appear in the gallbladder. An accurate diagnosis can be obtained by careful observation using ultrasonography.