Gallbladder adenocarcinoma
Gallbladder adenocarcinomas are usually asymptomatic until it is no longer curable. As such, early incidental detection is important, if the occasional patient is to be saved.
Epidemiology
Although overall uncommon, gallbladder adenocarcinoma is the most common primary hepatobiliary carcinoma and the 5th most common malignancy of the gastrointestinal tract 1.
Predominantly affects older persons with long-standing cholecystolithiasis, and as such is most common in elderly women (> 60 years of age, F:M ratio = 4:1) 1,3. Risk factors include 1:
- chronic cholecystitis - gallstones are seen in 70-90% of cases 3-4
- familial adenomatous polyposis syndrome (FAP)
- inflammatory bowel disease (IBD)
- porcelain gallbladder
Clinical presentation
Early in the course of the disease, patients are invariably asymptomatic, and as such a therapeutic window is usually missed. Eventually symptoms develop, at which time the mass is usually not resectable.
Clinical presentation depends on the direction in which the mass extends. In cases where biliary obstruction is created then jaundice is often the first presentation. If the malignancy is located in the body or fundus of the gallbladder, then extension into the liver or adjacent colon or small bowel can lead to local pain or bowel obstruction respectively.
Other symptoms include right upper quadrant pain, weight loss and anorexia.
Pathology
Over 90% of cases of gallbladder cancer are adenocarcinomas. Squamous cell carcinoma account for the majority of the remainder.
Radiographic features
Gallbladder adenocarcinomas present in one of three morphologies:
- intraluminal mass
- diffuse mural thickening
- mass replacing the gallbladder
- presumably the end result of progression from either 1 or 2
- most common presentation
CT
Typically gallbladder adenocarcinomas appear as large heterogenous masses, which may have engulfed gallstones or areas of necrosis. Patchy moderate contrast enhancement is usually seen.
Features of advanced disease include:
- intrahepatic biliary dilatation
- invasion into adjacent structures
- lymphadenopathy
- peritoneal carcinomatosis
- hepatic and distant metastases
MRI - MR cholangiography (MRC)
Dynamic MRI considered being useful and reliable in staging of advanced gallbladder cancer. MRI combined with MRC is sensitive in detection of obstructive jaundice, liver invasion as well as liver and lymph nodes metastasis. It may be more difficult to delineate the invasion to duodenum and omental metastasis by MRI 6. Reported sensitivity rates for direct hepatic invasion and lymph node invasion on MRI can be as high as 100 and 92% respectively 7.
Treatment and prognosis
Unfortunately, due to the largely asymptomatic nature of these tumours, presentation is typically late with the majority of tumours being large, unresectable, with direct extension into adjacent structures or distant metastases present at diagnosis.
Curative resection is only possible for localised early disease, which is usually found incidentally. This is reflected in the dismal prognosis 4:
- 1 year survival: 80%
- 5 year survival: 1-5%
Differential diagnosis
Clearly the differential will depend on the growth pattern of the tumour.
Intraluminal masses need to be distinguished from:
Mural thickening has a limited differential but is difficult to distinguish on imaging along. Possibilities include :
- cholecystitis
- gallbladder wall thickening due to portal hypertension
- adenomyomatosis
The differential for large tumours includes a number of nearby primaries with extension to the gallbladder:
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