Neoplasia USMLE Step 1 Practice Question
A 55-year-old man with a 10-year history of hepatitis C cirrhosis presents to clinic for surveillance imaging. He is asymptomatic with stable liver function tests and a platelet count of 95,000/μL. Ultrasound demonstrates a new 2.8-cm hypoechoic nodule in the right hepatic lobe. Serum alpha-fetoprotein (AFP) is 380 ng/mL (normal <20). Contrast-enhanced dynamic CT shows arterial phase enhancement of the nodule followed by venous phase washout, with no enhancement of the surrounding cirrhotic liver parenchyma. Which of the following best explains the characteristic arterial phase hyperenhancement seen in this lesion?
Answer choices
- APreferential blood supply from newly formed tumor vasculature that relies on hepatic arterial inflowCorrect answer
- BRapid arteriovenous fistulization within the tumor allowing arterial blood to shunt directly into hepatic veins
- CMass effect from the expanding tumor causing compression and redirection of portal venous flow
- DImpaired venous drainage in cirrhotic liver leading to prolonged contrast retention in the arterial phase
- ETumor-induced rupture of hepatic artery branches with extravasation of contrast into the tumor bed
- FPortal vein thrombosis causing compensatory increase in hepatic arterial flow throughout the liver
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.