Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (165 page)

   Benign tumors include adenomas, focal nodular hyperplasia, and hemangiomas. Adenomas are more commonly seen in women 30–40 years of age, mostly in the right lobe and can be as large as 10 cm in greatest dimension. There is often a history of oral contraceptive (estrogen) use. Focal nodular hyperplasia often presents as right-sided solid masses. Hemangiomas are most commonly benign, with hemorrhage and malignant transformation occurring rarely.

   Budd-Chiari syndrome (hepatic vein thrombosis) usually presents with hepatomegaly, pain, and severe, intractable ascites. Risk factors included hypercoagulable states, polycythemia vera, myeloproliferative syndromes, paroxysmal nocturnal, hemoglobinuria, and use of oral contraceptive pills.

   Metastatic tumors: After lymph nodes, the liver is the second most common metastatic site, probably due to its high vascularity from a dual arterial/venous blood supply. With the exception of primary brain tumors, any primary tumor can metastasize to the liver. The most common primary tumors derive from the GI tract, lung, breast, and melanoma. The usual presentation is with nonspecific, systemic symptoms such as weight loss, fever, and loss of appetite.

   A tender liver mass in a patient with an elevated WBC count and eosinophilia suggests a liver abscess and possibly parasitic infection.

   Radiologic studies

   Ultrasound is considered the primary screening examination for hepatic disease. In general, ultrasound is better for focal lesions than for parenchymal disease.

   The advantages include low cost, portability, and no ionizing radiation. Masses as small as 1 cm can be detected, and cystic masses or abscesses can be distinguished from solid masses. Doppler ultrasonography can assess the patency and direction of blood flow in the hepatic and portal veins (without contrast).

   The disadvantages include obscured images in the presence of bowel gas and obesity.

   CT scanning: In general, anatomic definition is more complete than with ultrasound. CT scanning is also better than ultrasound for showing diffuse parenchymal liver disease (fat shows ups as decreased density and hemochromatosis, or secondary iron overload shows up as increased density).

   The advantages include the ability to image in the setting of obesity and bowel gas.

•   Lesions as small as 1 cm can be distinguished.

•   With IV contrast, abscesses can usually be distinguished from tumors.

•   Dynamic scanning with IV contrast may also show cavernous hemangiomas.

•   Mass lesions can be biopsied under either ultrasound or CT guidance.

   The disadvantages include cost, radiation, and possible exposure to IV contrast.