Ultrasonographic features of fibrolamellar hepatocellular carcinoma

Objective To analyze and summarize the ultrasonographic features of fibrolamellar hepatocellular carcinoma (FLHCC). Methods The ultrasound images were retrospectively analyzed in 23 FLHCC cases which were confirmed by pathology, including the size, echogenicity, boundary and other features on gray scale ultrasound, color Doppler flow imaging and enhancement patterns on contrast-enhanced ultrasound (CEUS). Results Twenty-three patients had 23 lesions of FLHCC. The average age was (40.0±17.1) (15-77) years old and among them 3 cases had liver cirrhosis(13.0%). The maximum diameter of FLHCC lesions was 2.5-16.7 cm and the average was (7.2±4.3)cm. On gray scale ultrasound, 82.6% (19/23) lesions were hypoechoic, 78.3% (18/23) lesions showed cord-like or sheet-like hyperechoic area and 47.8% (11/23) lesions displayed strip-like echogenic attenuation in the center, with calcification in 17.4% (4/23) lesions. There were 91.3% (21/23) lesions showed peripheral and internal rich color flow signals on color Doppler flow imaging and 60.9% (14/23) with subcapsular thick blood vessels. All 8 FLHCC lesions displayed early and hyper-enhancement in the arterial phase and wash-out in the portal and delayed phases on CEUS. Internal nonenhanced scar-like area was appeared in all lesions on CEUS. Conclusions Patients with FLHCC are mostly young and few with liver cirrhosis. Ultrasonographic features are characterized by relatively large-sized mass with internal acoustic attenuation or calcification on gray scale ultrasound and hypervascularity with central scar on CEUS. Key words: Ultrasonography; Carcinoma, hepatocellular; Contrast-enhanced ultrasound