Abdominal pain in a man with hepatitis C

CASE

An 80-year-old man presented with right upper quadrant abdominal pain. He denied nausea, vomiting, diarrhea, or constipation. Urinalysis results were negative and the WBC count was normal, but liver function values were elevated. The patient had no history of alcohol abuse but did have chronic hepatitis C. A physical examination revealed tenderness over the right upper quadrant and hepatomegaly. The patient did not appear jaundiced. Ultrasonography (US) of the abdomen and CT were ordered (see the figures). What do these images reveal?

DISCUSSION

Figure 1 demonstrates a large mass within the right lobe of the liver. There is no evidence of cholelithiasis or cholecystitis. The CT scan performed to further characterize the mass shows a large, heterogeneous mass replacing most of the right lobe of the liver (see Figure 2). This finding is most compatible with a hepatoma, also known as hepatocellular carcinoma (HCC).

HEPATOCELLULAR CARCINOMA is the most common primary liver cancer. It is an aggressive disease; the median survival is 6 to 20 months after diagnosis, probably because HCC is usually not diagnosed until it has reached an advanced stage. This cancer occurs at a rate of approximately 4 per 100,000 people in the United States. In Asia and Africa, it is much more common, occurring in approximately 120 per 100,000 people, a sign of the increased incidence of hepatitis in these regions. With the relatively recent availability of hepatitis vaccines, the rate of occurrence may well decrease worldwide. The median age of diagnosis in the United States is 65 years, but in Africa and Asia patients are typically in their 40s or 50s when diagnosis occurs.

Persons with hepatitis B, hepatitis C, alcoholic cirrhosis, or cirrhosis due to other causes are at increased risk of developing HCC. Approximately 80% of patients with newly diagnosed HCC have pre-existing cirrhosis. Aflatoxins, carcinogens produced by fungi, can be found in contaminated food. These can increase the risk of developing a hepatoma. Aflatoxins are usually found in subtropical regions. Hereditary hemochromatosis is also associated with an increased risk of HCC.

Symptoms are usually related to advancing liver disease and may include pruritis, jaundice, hepatomegaly, splenomegaly, hepatic encephalopathy, weight loss, abdominal pain, ascites, or variceal bleeding. Other symptoms are pedal edema, enlarged hemorrhoidal veins, periumbilical collateral veins, early satiety, or—rarely—shock due to rupture or bleeding of the tumor.

Alpha fetoprotein (AFP) levels can assist with diagnosis. Although approximately 75% of patients with HCC will have an elevated AFP level, the level can be normal in approximately 40% of patients with a hepatoma that is less than 2 cm in size. If the tumor is between 2 and 5 cm, the AFP level is normal in approximately 28% of patients. AFP levels can also be elevated in other conditions, such as pregnancy, gonadal tumors, and acute or chronic viral hepatitis. And not all hepatomas secrete AFP. For unknown reasons, those that do not may hold a better prognosis than do those that secrete AFP. Screening at-risk patients for HCC, if performed, should include AFP level and imaging. AFP levels alone are not adequate.

IMAGING of suspected hepatomas includes the use of US, CT, and occasionally MRI. US is the least expensive imaging study but is often operator-dependent. It also has decreased sensitivity for detecting small lesions. It can, however, be used to assess portal vein patency. When CT is utilized, it is best to order a triple phase study of the liver. This will include images performed without contrast and images taken after contrast administration, during the early arterial and late (portal) phases. Acquiring the images in the three phases allows more tumors to be detected. CT sensitivity for tumor detection may be decreased in patients with nodular cirrhosis. In these instances, MRI may be a more appropriate imaging choice. Imaging is important to determine tumor size, number, location, patency, and/or invasion of adjacent arteries or veins and to detect metastasis. HCC may metastasize to the lungs, portal vein, periportal nodes, bone, or brain.

BIOPSY may also be necessary to establish a diagnosis of HCC. However, there is controversy concerning
the possibility of tumor seeding along the biopsy needle tract. The diagnosis can be made without biopsy in the following circumstances: (1) two imaging modalities reveal an enlarging mass in a cirrhotic liver, with one of the studies demonstrating contrast enhancement; (2) one imaging study demonstrates an enlarging mass in a cirrhotic liver, and the AFP level is greater than 500 to 1,000 ng/mL; or (3) the lesion is going to be resected regardless of its histology.

Tumors in the 2- to 3-cm range may represent dysplastic nodules and may be premalignant. Biopsy is important to distinguish them from HCC. In lesions less than 2 cm, the false-negative rate can be as high as 30% to 40%.

STAGING of HCC is usually done via the TNM classification system. CLIP (Cancer of the Liver Italian Program) scoring—a system that takes into account tumor morphology, AFP level, portal vein involvement, ascites, and the overall state of the liver—is used in an attempt to predict prognosis. Prognosis greatly depends on the size of the tumor and liver function.

TREATMENT options for hepatomas include tumor resection, liver transplantation, radiofrequency ablation, transarterial embolization, ethanol injection, cryoablation, and chemotherapy. Cure is usually possible in about 5% of patients and is achieved using tumor resection or liver transplantation. Resection is considered in patients with a tumor less than 5 cm in size that is confined to one lobe of the liver and when there is no vascular invasion. Candidates for liver transplantation are usually given priority when a liver becomes available. These are usually patients with one tumor measuring less than 5 cm in size or with up to three tumors, each measuring less than 3 cm in size. Ablation, embolization, ethanol injection, or chemotherapy are usually used as palliative measures. JAAPA

Julie Vajnar is the department editor for Diagnostic Imaging Review and practices in a radiology group at North Oaks Health System, Hammond, Louisiana. She has indicated no relationships to disclose relating to the content of this article.