Carcinoma of the gallbladder is the fifth most common cause of death from GI malignancy. Most cases occur after the age of 50. Gallbladder carcinoma is three times more frequent in females. There is a high association (65-95%) with gallstones. The disease is almost always advanced at the time of detection; the early stages are asymptomatic. It may be an incidental finding at cholecystectomy or on imaging studies.

Most lesions are well-differentiated adenocarcinoma. Three primary morphologic patterns are seen (Film .9): 1) an intraluminal polypoid mass (15-25%), 2) focal or diffuse wall thickening (20-30%), and 3) a fungating mass replacing the gallbladder (40-65%) and extending to the adjacent liver.

Direct spread to contiguous structures is the most frequent route of extension and involvement of the medial segment of the left lobe of the liver is most commonly seen. Biliary obstruction is common.

The preoperative diagnosis was rarely made prior to ultrasound and CT; OCG showed non-visualization. On US and CT, the most frequent findings are gallstones and a mass in the gallbladder fossa extending to the adjacent liver. This appearance may be difficult to distinguish from cholecystitis complicated by abscess or perforation. Dilated bile ducts from tumor involvement and obstruction of the CHD may also be seen. Other findings seen on US or CT include gallbladder wall thickening, an intraluminal polypoid mass, nodal involvement or metastases. When the mass is confined to the gallbladder, the sonographic appearance may be indistinguishable from gallstones or the presence of stones may obscure the lesion.

When biliary obstruction is present, direct cholangiography is helpful to outline the exact nature and site of obstruction. This may be difficult to assess by CT or US. On PTC, the common hepatic duct above the cystic in the area of the porta hepatis is most frequently affected. The common duct may be displaced medially by the tumor mass. If the lesion extends higher into the liver, multiple sites of obstruction can be present. Because of cystic duct involvement, the gallbladder usually does not fill. The differential diagnosis of the cholangiographic appearance includes obstruction from metastatic nodes in the porta hepatis and primary cholangiocarcinoma.