A previously healthy 36-year-old woman comes to the physician because of a one-month history of right upper quadrant pain that occurs after meals. Vitals are within normal limits. There is no jaundice or scleral icterus. Serum studies are unremarkable. Abdominal ultrasonography shows cholelithiasis and a 4-cm hepatic mass. Abdominal CT shows a hepatic mass with a central scar. Which of the following is the most appropriate next step in diagnosis?
Hepatitis B serology
MRI of the liver
No further studies indicated
Serum alpha-fetoprotein concentration
Serum anti-mitochondrial antibodies
