5.  The autopsy of a 40-year-old woman reveals hemoperitoneum and a subcapsular hemorrhagic mass in the right hepatic lobe. The mass is partially encapsulated, and the adjacent liver parenchyma appears compressed. This picture shows its histologic composition. Conspicuous thick-walled vessels are scattered throughout the lesion, but there are no identifiable central veins or portal tracts. Which of the following is the most important predisposing factor for this lesion?

  6.  A hepatocellular adenoma (HCA) removed from the liver of a 45-year-old man shows prominent cytologic atypia. Which of the following immunohistochemical features is this HCA type most likely to display?

  7.  A well-demarcated subcapsular nodule is identified by MRI in the right hepatic lobe of a 35-year-old woman with abdominal discomfort. The lesion is removed. Its cut section is shown in this macroscopic photograph. Microscopic examination shows liver lobules with fatty changes separated by thick fibrous bands. The central scar contains thick-walled arteries. These gross and microscopic features are consistent with:

  8.  A 50-year-old woman with rheumatoid arthritis presents with signs and symptoms of portal hypertension. An abdominal MRI is suggestive of liver cirrhosis. A needle biopsy reveals areas of congestion and atrophy alternating with areas of expanded lobules. Central veins are not seen. Which of the following mechanisms plays a crucial role in the pathogenesis of this disorder?

  9.  Increasing utilization of screening and surveillance programs, combined with improved accuracy of imaging techniques, makes detection of small nodular lesions more common in cirrhotic livers. Some of these nodules may be cancer precursors. Which of the following nodular lesions has the highest likelihood to progress to hepatocellular carcinoma?

10.  Which of the following is the most reliable indicator of malignancy in a needle biopsy of a nodule within a cirrhotic liver?

11.  The following is a list of factors or conditions that predispose to the development of hepatocellular carcinoma (HCC). In which of them does HCC occur constantly in noncirrhotic livers?

12.  Which of the morphologic patterns of HCC is represented in this photomicrograph?

13.  Which of the following immunohistochemical stains has a specificity for HCC that is close to 100%?

14.  A patient undergoes partial hepatectomy for a neoplasm. The tumor consists of nodules of large cells with prominent nucleoli, separated by broad fibrohyaline bands, as shown in this picture. Which of the following is the most likely clinical setting associated with this tumor type?

15.  A 16-month-old baby is diagnosed with a liver tumor. On histologic examination, the tumor is characterized by a “light/dark” biphasic pattern, as shown in this low-power photomicrograph. This tumor is most likely a:

16.  The cut surface of a liver removed at autopsy shows scattered white nodules in the liver parenchyma. Histologically, they consist of disorderly clusters of bile ductules lined by bland epithelial cells without identifiable connection with the bile system. These features are most consistent with: