Presentation
A liver lesion was incidentally detected in this patient during a recent pelvic ultrasound (when the kidneys were assessed). There was no history of liver disease. No oral contraceptive use.
Patient Data
There is a 1.35 cm sharply circumscribed rounded lesion in segment VI of the liver. The lesion has a hypoechoic rim. No color Dopper signal was detected within. Surrounding liver parenchyma is normal in appearance.
Contrast-enhanced ultrasound
Dynamic images of the segment VI lesion following intravenous injection of 2ml SonoVue® (sulphur hexafluoride microbubbles).
Dynamic images demonstrate avid arterial enhancement commencing approximately 11 s post injection of contrast. The first 4-5 s of the clip clearly show a centrifugal, i.e. 'inside-out' pattern of enhancement. Select still images show equilibrium with liver parenchyma; there is no washout. The lesion is more difficult to see on the control B-mode image on the right hand side during portal venous phase because microbubbles present within the vascular spaces of the lesion are also visible on B-mode.
Case Discussion
Centrifugal enhancement in a liver lesion is most commonly seen in focal nodular hyperplasia (FNH), and this pattern is a good predictor of these lesions at contrast-enhanced ultrasound 1. However, centrifugal enhancement can be an atypical feature of liver hemangiomas 2 (the more commonly seen pattern in hemangiomas is centripetal).
In this case, centrifugal enhancement can be observed in a lesion as small as 1.4 cm. The likely diagnosis is FNH, although the imaging is not diagnostic. There are no features to suggest a malignant process. This patient will be followed up with B-mode ultrasound to ensure stability.