A case of fibrolamellar hepatocellular carcinoma, occurring in a 13 year-old girl with the characteristics of the dynamic enhancement observed during contrast-enhanced ultrasound within the tumour and within vascular extension into the portal vein is reported. The lesion showed marked hypervascularity in the early arterial and arterial phases with irregular, tortuous vessels. During the early portal phase, centripetal filling of the tumour was observed, except in an irregular area and adjacent hypo-enhancing bands, related to a central scar, on subsequent CT and MRI images. Centrifugal wash-out led to the absence of sustained enhancement during the late phase. Similar enhancement patterns were observed within the portal tumoural thrombosis, and evaluation of its extension was easy on delayed images. Contrast-enhanced ultrasound is a useful diagnostic tool for the characterisation and evaluation of extension of such a rare malignant hepatic tumour.