CASE 2782 Published on 20.07.2005

A focal liver lesion with central scar in a cirrhotic patient

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Iannaccone R, Marin D, Celestre M, Filpo M, Pasqualini V

Patient

55 years, male

Categories
No Area of Interest ; Imaging Technique CT, CT
Clinical History
A 55-year-old male cirrhotic patient presented with a focal liver lesion with a central scar.
Imaging Findings
The patient was referred to our Institute because of elevated alpha fetoprotein serum levels (>500 ng/ml) and ascites refractory to therapy. Ultrasonography showed a hypoechoic lesion of the VI segment and, thus, quadruple-phase multidetector CT was performed. Unenhanced, arterial (30 s), portal venous (70 s), and delayed (180 s) phases were acquired, after i.v. contrast material administration (injection rate 4 ml/s). CT images showed several findings of cirrhosis, including polylobulated liver margins, left liver and caudate lobe hypertrophy, and indirect signs of portal hypertension (i.e. varices, splenomegaly, ascites). At the level of the VI segment, CT identified a well-marginated lesion measuring 4 cm in diameter. On unenhanced scan, the lesion presented the same density of the surrounding liver parenchyma, apart from a central scar, which was relatively hypodense. After contrast medium administration, the lesion showed heterogeneous enhancement on the arterial phase, while progressively washing-out on the portal venous and delayed phases (reduced portal venous flow). The central scar remained hypodense on all contrast-enhanced phases. Hepatocellular carcinoma (HCC) was diagnosed at fine needle biopsy. The patient was treated with percutaneous radiofrequency ablation of the lesion.
Discussion
HCC is the fifth most common tumor, and the third cause of cancer-related death in Western countries. In recent years, tumor-incidence has been raising, due to widespread surveillance programs and improved diagnostic capabilities. On the other hand, earlier diagnosis allows curative therapeutic procedures (surgical resection, percutaneous ablation, or liver transplantation), improving the long term prognosis. Ultrasonography (US) is the first-line imaging modality in the diagnosis of HCC, and is repeated every six months, as a screening tool in high risk patient populations. CT and MR scan are performed when there is a suspicion of the presence of a tumor in the liver because of elevated αFP serum levels and/or a new lesion discovered at US examination. The tumor presents an arterial vascular supply, which rapidly enhances on the arterial phase (25–30 s). Conversely, on the portal venous phase (60–70 s), tumor vascularity decreases if compared to the liver and, thus, the lesion shows lower density than the surrounding parenchyma (wash-out sign). In some instances, a pseudocapsule may be seen on delayed phase images, due to the peripheral vascular drainage of the lesion, through small portal branches. If present, central scar is identified as a hypoattenuating area compared with both the surrounding tumor and the liver parenchyma. Central fibrous scar is most commonly found in HCCs arising in non-cirrhotic livers. Since a central area of fibrous scarring has been described in several types of liver tumors, including focal nodular hyperplasia, hemangiomas, fibrolamellar HCC, colangiocarcinoma, and hepatic metastases, care must be taken in image interpretation. However, a clinical history of cirrhosis and typical imaging findings of arterial enhancement and portal venous wash-out strongly suggest the diagnosis of HCC.
Differential Diagnosis List
Hepatocellular carcinoma.
Final Diagnosis
Hepatocellular carcinoma.
Case information
URL: https://eurorad.org/case/2782
DOI: 10.1594/EURORAD/CASE.2782
ISSN: 1563-4086