Infiltrative Hepatocellular Carcinoma: What Radiologists Need to Know

Abstract

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. The macroscopic growth pattern of HCC is subdivided into three categories: nodular, massive, and infiltrative. Infiltrative HCC accounts for 7%-20% of HCC cases and is confirmed at pathologic analysis on the basis of the spread of minute tumor nodules throughout large regions of the liver. Infiltrative HCC may represent a diagnostic challenge because it is often difficult to distinguish from background changes in cirrhosis at imaging. Infiltrative HCC usually spreads over multiple hepatic segments, occupying an entire hepatic lobe or the entire liver, and it is frequently associated with portal vein tumor thrombosis. The tumor is usually ill defined at ultrasonography and shows minimal and inconsistent arterial enhancement and heterogeneous washout at contrast material-enhanced computed tomography and magnetic resonance (MR) imaging. The tumor may be more visible among the surrounding liver parenchyma at diffusion-, T1-, and T2-weighted MR imaging. Several liver diseases can mimic the infiltrative appearance of this malignancy, including focal confluent fibrosis, hepatic fat deposition, hepatic microabscesses, intrahepatic cholangiocarcinoma, and diffuse metastatic disease (pseudocirrhosis). The prognosis for patients with infiltrative HCC is poor because the tumor is often markedly advanced and associated with vascular invasion at presentation. Survival after surgical resection is decreased; thus, infiltrative HCC is a contraindication for resection and transplantation. Knowledge of the key tumor characteristics and imaging findings will help radiologists formulate a correct and timely diagnosis to improve patient management.

Congenital absence of the portal vein complicated by hepatocellular carcinoma in the liver of an adult woman: review of imaging, literature and management

“…For this reason CT or MRI is preferred to trace the course of the SMV and SV [13] . It has been shown that PV thrombosis can results in parenchyma perfusion changes readily concealing the presence of tumor on enhanced images [14] . Hyperintensity on T2 and diffusion sequences can indicate the presence of HCC, particularly infiltrative HCC with corresponding hypointensity in comparison to liver parenchyma on T1 sequences [14] .…”

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“…Uniform signal loss between dual-echo in-phase and opposed-phase gradient-echo T1-weighted MRIs suggests fat deposition. 6 …”

“…4 In 225 patients with HCC confirmed by pathologic analysis at liver explantation, the lesionbased sensitivity of US was only 46%. 6 Currently, all major clinical practice guidelines endorse multiphasic CT and MRI with extracellular contrast agents as first-line modalities for diagnosing and staging HCC. Both modalities provide excellent sensitivity for detecting nodular HCCs larger than 2 cm, modest sensitivity for 1-to 2-cm HCCs, and poor sensitivity for HCCs smaller than 1 cm, and it is not yet clear which modality is superior.…”

“…Contrast-enhanced images are acquired during the late arterial phase (~15-20 s after initiating aortic threshold-based scanning), portal venous phase (~30-60 s after initiating scan), and delayed phase (> 120 s after injecting contrast material). 6 The recommended minimal technical parameters for dynamic contrast-enhanced MRI of the liver include the use of a 1.5-T imaging unit equipped with a phased-array coil. The protocol should include unenhanced gradient-echo T1-weighted dual-echo images and T2-weighted spin-echo images (with and without fat saturation).…”

“…Contrast-enhanced images should be obtained during the late arterial phase (bolus tracking), the portal venous phase (35-55 s after initiating arterial phase), and the delayed phase (120-180 s after injecting contrast material). 6 The advantages of CT are that it is widely available, rapid, robust, and less expensive compared with MRI and requires less expertise to perform and interpret images. Disadvantages include radiation exposure and relatively low soft-tissue contrast.…”