This limitation applies to all cross-sectional imaging techniques, including US, CT, and MRI.8-10 US examination is a common initial screening method by which FNH is discovered. serum level of alanine aminotransferase was 22 IU/L, aspartate aminotransferase was 19 IU/L, alkaline phosphatase was 75 IU/L, and total bilirubin was 0.6 mg/dL. The levels of tumor markers were alpha fetoprotein at 5.9 ng/mL, carcinoembryonic antigen at 1.1 ng/mL, and carbohydrate antigen 19-9 at 7 U/mL. The results for hepatitis B surface antigen, anti-HBs, and anti-hepatitis C computer virus antibody were unfavorable. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a hypervascular mass PD 123319 ditrifluoroacetate with a central scar in S5 of the liver (Fig. 2). == Physique 1. == Ultrasonography showed a mixed echoic large mass (6.44.8 cm) (arrows) on the right hepatic lobe. There was no evidence of cirrhosis in the surrounding liver tissue. == Physique 2. == (A-D) CT images obtained at the same level. A high-density mass (arrows) PD 123319 ditrifluoroacetate with a low-density center was evident during the arterial phase (B). During the portal (C) and delayed (D) phases, the mass was iso-or hypodense. (E) T1-weighted MRI showed an isointense lesion with a hypointense central scar (arrows). (F) T2-weighted MRI showed a slightly hyperintense lesion with a more hyperintense central scar (arrows). (G) During the arterial phase, in Primovist (gadolinium EOB-DTPA; Schering, Germany)-enhanced dynamic T1-weighted MRI the lesion was hyperintense but the central scar remained hypointense. (H) At 20 moments after Primovist injection the lesion remained hyperintense compared to the surrounding liver parenchyma (arrows). CEUS was subsequently performed using a color Doppler ultrasonic scanner (Prosound alpha 10 premier, Aloka, Tokyo, Japan) with the injection of contrast agent (SonoVue, Bracco Diagnosis, Italy) for PD 123319 ditrifluoroacetate real-time dual-flame harmonic imaging of the mass. The mass appeared spoke-wheel like during the Rabbit Polyclonal to ZNF695 arterial phase, and its enhancement persisted until the late phase (Fig. 3, Video atwww.koreanjhepatol.org). == Physique 3. == (A) Pre-enhanced phase on CEUS. (B-D) During the arterial phase (10~13 seconds after a bolus injecting of contrast agent) there was a spoke-wheel-like centrifugal filling of contrast agent and a markedly hyperechoic mass (arrows), which is usually attributable to the presence of a central feeding artery and radial arterial vascularity. Sustained enhancement, which appeared slightly hyperechoic or isoechoic relative to the surrounding liver parenchyma, was noticed until the portal venous phase. (E) (45 seconds after contrast-agent injection) and the late phase. (F) (3 minutes after contrast-agent injection). The central scar was hypoechoic during all of the phases. A percutaneous fine-needle-aspiration biopsy was performed under ultrasound guidance, and a histologic examination of the biopsy specimen showed a fibrous scar with anomalous blood vessels (Fig. 4). The characteristic imaging findings and the biopsy results led to a final diagnosis of FNH of the liver. He was recommended to receive regular follow-up of the hepatic lesion. == Physique 4. == Microscopic findings of a biopsy specimen showed hyperplasia of normal hepatocytes, a fibrous scar with irregular thick-walled blood vessels (arrow), and lymphocytic infiltration (H&E stain, 200). == Conversation == The prevalence of FNH is usually approximately 0.9%, and is more common in females (80~95% of cases) in the third or fourth decade of life.1Some studies have shown that FNH develops most often in males around the middle age.4The pathogenesis of FNH is not well characterized. FNH is considered secondary to a hyperplastic response to a regenerative nonneoplasic nodule caused by a congenital vascular malformation. FNH lesions are usually solitary (80% of cases) with diameters >5 cm. Histological characteristics include a connective tissue central stellar scar with a large arterial vessel and a septum.5 FNH presents most commonly as an incidental finding on hepatic imaging (US, CT, and MRI) with no associated symptoms, normal liver function test results, and no elevation of serum levels of tumor markers such as alpha fetoprotein. The reported incidence of symptomatic lesions in large series has ranged from 10% to 59%.6,7The most common symptom is right-upper quadrant pain. Other symptoms include the sensation of a mass in the right-upper quadrant, nausea, and other gastrointestinal symptoms. Symptoms do not appear until the lesion is large enough to compress surrounding structures or induce the sensation of a mass, which on average occurs when the size is greater than 7 cm.7 Given the benign nature of this lesion, it is essential to differentiate it from more dangerous liver masses, primarily hepatocellular carcinoma. Therefore, the ability to identify the radiologic characteristics of FNH is usually important to avoiding unnecessary medical procedures, biopsy, and follow-up imaging. FNH is typically diagnosed PD 123319 ditrifluoroacetate using several complementary imaging techniques. In patients for whom the diagnosis is not clearly decided from imaging.