Fortuitously discovered liver lesions

Abstract

The fortuitously discovered liver lesion is a common problem. Consensus might be expected in terms of its work-up, and yet there is none. This stems in part from the fact that there is no preventive campaign involving the early detection of liver tumors other than for patients with known liver cirrhosis and oncological patients. The work-up (detection and differential diagnosis) of liver tumors comprises theoretical considerations, history, physical examination, laboratory tests, standard ultrasound, Doppler ultrasound techniques, contrast-enhanced ultrasound (CEUS), computed tomography and magnetic resonance imaging, as well as image-guided biopsy. CEUS techniques have proved to be the most pertinent method; these techniques became part of the clinical routine about 10 years ago in Europe and Asia and are used for a variety of indications in daily clinical practice. CEUS is in many cases the first and also decisive technical intervention for detecting and characterizing liver tumors. This development is reflected in many CEUS guidelines, e.g., in the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) guidelines 2004, 2008 and 2012 as well as the recently published World Federation for Ultrasound in Medicine and Biology-EFSUMB guidelines 2012. This article sets out considerations for making a structured work-up of incidental liver tumors feasible.

Keywords: Contrast-enhanced ultrasound; Focal nodular hyperplasia; Guidelines; Hemangioma; Hepatocellular carcinoma; Metastasis; Recommendations; Ultrasonography.

Figure 1

Hemangioma. Large hemangioma in B-mode (A), with typical peripheral nodular contrast enhancement (B) and centripetal fill-in (C). GB: Gallbladder.

Figure 2

Shunt hemangioma. Shunt hemangiomas are typically small (often < 20 mm) with abundant arterio(porto-)venous shunts (functionally described as high flow hemangiomas). They are often surrounded by less fat-containing hypoechoic liver parenchyma (A, B) due to the dominant arterial blood flow in comparison to the reduced portal venous perfusion. Arterial contrast enhancement of the shunt-hemangioma is also shown (C, D). H: Hemangioma; F: Less fat-containing hypoechoic area. Reproduced with permission from Dietrich et al[65].

Figure 3

Teleangiectatic focal nodular hyperplasia. Pedunculated liver tumor, histologically teleangiectatic focal nodular hyperplasia with signs of peliosis. A: B-mode imaging shows heterogenous echogenicity; B: Contrast-enhanced ultrasound reveals central arterial blood supply; C: Real-time elastography shows harder periphery and softer central portions of the lesion.

Figure 4

Focal nodular hyperplasia. A: In addition to conventional contrast-enhanced ultrasound (CEUS), parametric CEUS displays also the timeline of contrast enhancement (early enhancement in yellow, later enhancement in blue); B: Histologically proven. B-mode revealed isoechoic lesion, very difficult to identify. Shear wave elastography reveals very hard tissue of the lesion, shown in red in comparison to the surrounding soft liver parenchyma.

Figure 5

Focal fatty sparing. A: Focal fatty changes may simulate masses on conventional B-mode ultrasound; B: In the arterial, portal venous and late phases, focal fatty changes show similar enhancement patterns to that of the adjacent liver parenchyma. Contrast-enhanced ultrasound is helpful for the identification of the centrally located arteries. Typically centrally located arteries (and often also portal venous branches and hepatic veins) can be identified. Dynamic vascular pattern improves contrast imaging. Reproduced with permission from Cui et al[120].

Figure 6

Liver metastasis. In contrast to the variably enhancing arterial phase (A-C), liver metastases are typically hypoenhancing during the portal venous (sinusoidal) phase (D) which facilitates their reliable diagnosis.

Figure 7

Hepatocellular carcinoma with arterial hyperenhancement (A) and hypoenhancement in the portal venous phase (B).