Gastrointestinal ImagingE2819. Non HCC Solid Liver Lesions Occurring in Chronic Liver Disease: What the Radiologist Needs to Know
Lewis S, Pagano A, Song C, Chatterji M, Taouli B. Icahn School of Medicine at Mount Sinai, New York, NY
Address correspondence to S. Lewis (Sara.Lewis@mountsinai.org)
Background Information: Hepatocellular carcinoma (HCC) is the most common primary liver cancer. The major risk factors for development of HCC are chronic liver disease and cirrhosis. The American Association for the Study of Liver Diseases practice guidelines recommend imaging surveillance every 6 months for high-risk patients. Patients with HCC may be given Model for End-Stage Liver Disease exception points, increasing the patient’s priority on the liver transplant waiting list. Given that HCC is most commonly diagnosed by established imaging criteria, accurate characterization of lesions arising in the cirrhotic liver is essential to direct appropriate management and to avoid unnecessary intervention. Both common and unusual malignant and benign solid liver lesions other than HCC may also be seen in this patient group. Malignant lesions include intrahepatic cholangiocarcinoma (ICC), mixed HCC-ICC tumors, and metastasis. Benign lesions and pseudo lesions include regenerative and dysplastic nodules, focal nodular hyperplasia, arterioportal shunting, hemangioma, confluent hepatic fibrosis, and focal fat deposition. Very rarely, adenoma, angiomyolipoma, or an inflammatory pseudo tumor can be seen. In this review, we will describe the typical CT and MRI characteristics and imaging pitfalls of malignant and benign solid liver lesions occurring in chronic liver disease and highlight essential points to aid in making a correct diagnosis.
Educational Goals/Teaching Points: The goals of this exhibit are to identify the typical and atypical imaging characteristics of solid liver lesions other than HCC that can occur in chronic liver disease, describe key imaging characteristics that may assist in distinction from HCC, and integrate the CT and MRI findings with clinical history, laboratory values, and histopathologic findings to allow for accurate lesion characterization.
Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: This educational exhibit will illustrate various imaging findings of common and uncommon solid liver lesions other than HCC that may also be present in chronic liver disease. The presence of background liver fibrosis and cirrhosis may alter the typical CT or MRI appearance of these liver lesions. For example, small ICCs may demonstrate solid hypervascular enhancement and washout, mimicking HCC. Hemangiomas may demonstrate slower progressive peripheral nodular enhancement and lower T2 signal than the typical presentation, mimicking ICC. Using a case-based approach, we will illustrate certain imaging and clinical features that are essential to generating a relevant differential diagnosis and aid in accurate lesion characterization.
Conclusion: Cross-sectional imaging, including CT and MRI, are essential in the characterization of focal liver lesions and have significant impact on both patient management and liver transplant allocation in patients with chronic liver disease and cirrhosis. Malignant and benign lesions other than HCC may occur in these patients, and the radiologist’s knowledge of the typical and atypical imaging appearance of these lesions is essential for correct lesion characterization.