Lectures

Focal liver lesion: nonlinear contrast-enhanced ultrasound imaging

Enhancement Patterns of Benign Focal Lesions

Inflammatory Pseudo Tumors

The inflammatory pseudo tumor of the liver is very uncommon, and is characterized by a well-defined mass consisting of chronic inflammatory cell infiltration and fibrosis (Ishak et al., 1994). Prevalent necrotic nodules are also reported (Iwase et al., 2002, Abbey-Toby et al., 2003). The etiology of this disease is unclear: micro-organisms from food, cholangitis or hepatic involvement from chronic intra-abdominal infection with ascending infection via the portal blood stream could explain the inflammatory hepatic lesion due to oblitering phlebitis (Horiuchi et al., 1990). On conventional ultrasound large, inhomogeneous, hypo-echoic masses with multiple thin septae are identified (Nam et al., 1996). In our experience small encapsulated nodules may be observed. Color Doppler presents some flow signals in the periphery of the lesion in large masses and no flow signal in the small nodules. Contrast-enhanced ultrasound shows marginal enhancement in the arterial phase, while hypo enhancement areas are demonstrated in the portal and parenchymal phases. Small nodules present hypo or lack of enhancement especially in the late phase. This ambiguous behavior may mimic metastases.

Case A-8.1.1

Focal liver lesion in segment 7, solid hypoechoic, intralesion vessels to color-power Doppler. In arterial phase early enhancement with early wash-out in portal and parenchymal phases and lack of enhancement in late phase. C.R: inflammatory pseudotumor

Case A-8.1.2

3 month later follow-up. Reduction of dimension; not evidendence of enhancement in arterial phase, lack of enhancement in late phase. C.R: inflammatory pseudotumor

Case A-8.2

3 Focal liver lesions in segment 5-8 and 7, solid hypoechoic. In arterial phase it is not found evidence of enhancement; in portal and parenchymal phases lack of enhancement. C.R: inflammatory pseudotumor mimic metastases