Liver and Biliary Tract Tumors for USMLE Step 2
Liver and Biliary Tract Tumors for the USMLE Step 2 Exam
Liver Tumors
- Hepatocellular Carcinoma (HCC):
- Epidemiology:
- HCC is the most common primary liver cancer, accounting for 80-90% of cases.
- Associated with cirrhosis, commonly from hepatitis B, hepatitis C, alcoholic liver disease, and nonalcoholic steatohepatitis (NASH).
- Risk Factors:
- Chronic viral hepatitis (HBV, HCV), alcohol use, metabolic syndromes (diabetes, obesity), aflatoxin exposure, and hereditary conditions like hemochromatosis.
- Clinical Presentation:
- Early disease is often asymptomatic; advanced cases present with weight loss, abdominal pain, jaundice, and ascites.
- Signs of decompensated cirrhosis may include variceal bleeding and hepatic encephalopathy.
- Diagnosis:
- Imaging with CT or MRI shows characteristic arterial phase enhancement with venous washout.
- Alpha-fetoprotein (AFP) levels are elevated in 50-70% of cases.
- Treatment:
- Surgical resection or liver transplantation for early-stage disease.
- Transarterial chemoembolization (TACE) for intermediate cases and sorafenib or newer tyrosine kinase inhibitors for advanced disease.
- Hepatic Adenoma:
- Epidemiology:
- A benign liver tumor linked to oral contraceptive use and anabolic steroid use.
- Common in women of reproductive age.
- Clinical Presentation:
- Often asymptomatic, but large adenomas can cause abdominal pain or hemorrhage.
- Diagnosis:
- MRI is preferred, showing a hypervascular lesion.
- Treatment:
- Discontinue oral contraceptives; surgical resection if the adenoma is >5 cm or symptomatic due to the risk of rupture or malignant transformation.
- Focal Nodular Hyperplasia (FNH):
- Epidemiology:
- A benign liver lesion, often found incidentally, primarily affecting young women.
- Clinical Presentation:
- Asymptomatic and rarely causes complications.
- Diagnosis:
- MRI shows a central stellate scar with arterial enhancement.
- Treatment:
- No treatment needed unless symptomatic.
Biliary Tract Tumors
- Cholangiocarcinoma:
- Epidemiology:
- A malignancy of the bile ducts, classified as intrahepatic or extrahepatic.
- Associated with primary sclerosing cholangitis (PSC), liver fluke infections, and chronic biliary tract inflammation.
- Clinical Presentation:
- Painless jaundice, pruritus, and dark urine are classic signs of extrahepatic cholangiocarcinoma.
- Intrahepatic tumors may cause abdominal pain and hepatomegaly.
- Diagnosis:
- MRI/MRCP or CT shows bile duct dilation or mass.
- CA 19-9 is often elevated but nonspecific.
- Treatment:
- Surgical resection for early-stage disease.
- Adjuvant chemotherapy (gemcitabine, cisplatin) is often used.
- Gallbladder Cancer:
- Epidemiology:
- Rare, but the most common biliary tract cancer.
- Associated with chronic gallstone disease, porcelain gallbladder, and chronic cholecystitis.
- Clinical Presentation:
- Often asymptomatic in early stages; late symptoms include right upper quadrant pain, jaundice, and weight loss.
- Courvoisier sign (palpable gallbladder) may indicate obstructive jaundice from malignancy.
- Diagnosis:
- Ultrasound or CT detects gallbladder masses.
- Treatment:
- Surgical resection is the only curative treatment, but most cases are diagnosed at an advanced stage.
- Chemotherapy or radiation may be used for unresectable cases.
Key Points
- Hepatocellular carcinoma (HCC) is the most common liver cancer, associated with cirrhosis from hepatitis B, hepatitis C, and alcohol use. Diagnosis is made by imaging and AFP levels, and treatment options include resection, transplantation, and systemic therapies.
- Hepatic adenoma is linked to oral contraceptive use and may require surgical resection if large or symptomatic.
- Cholangiocarcinoma, a malignancy of the bile ducts, presents with painless jaundice and has a poor prognosis. Surgical resection is the best chance for cure.
- Gallbladder cancer is rare and associated with chronic gallstones, presenting with right upper quadrant pain and jaundice in advanced cases.