Real-time contrast-enhanced ultrasonography of resected and immunohistochemically proven hepatic angiomyolipomas. ACTA ACUST UNITED AC. 2010;35:676-682. [PMID: 20020286 DOI: 10.1007/s00261-009-9592-x]

Washout on Contrast-Enhanced Ultrasound of Benign Focal Liver Lesions-A Review on Its Frequency and Possible Causes

In all imaging methods, including contrast-enhanced ultrasound (CEUS), enhancement in the late phase (LP) is an important criterion for differentiating between benign and malignant focal liver lesions (FLLs). In general, malignant liver lesions are characterized by hypoenhancement and washout in the LP. A lesion with LP hyperenhancement or isoenhancement in the non-cirrhotic liver is usually benign. However, LP hypoenhancement in benign lesions is not so rare, and is even normal and the standard for some lesions, and there are exceptions for each tumor entity that can represent a diagnostic challenge. Knowing these contrast patterns and exceptions is key for correct diagnosis and patient management. The following narrative review describes the contrast behaviors and the frequency of washout and LP hypoenhancement for common as well as rare benign liver lesions and analyzes its causes.

Clinical and Contrast-enhanced Ultrasound Characteristics of Epithelioid and Classic Hepatic Angiomyolipoma: Comparison With Alpha-fetoprotein-negative Hepatocellular Carcinoma

Hepatic angiomyolipoma (HAML) comprises epithelioid angiomyolipoma (EAML) and classic hepatic angiomyolipoma (CAML). The imaging appearance of HAML varies widely, and EAML is more easily misdiagnosed as hepatocellular carcinoma (HCC) than as CAML. The clinical and contrast-enhanced ultrasound (CEUS) features of CAML, EAML and HCC with negative alpha-fetoprotein protein expression (HCC[AFP-]) were retrospectively reviewed. The hyper-vascular type was more commonly found in CAML and EAML lesions than in HCC lesions. Most lesions were hyper-enhanced in the arterial phase. CAMLs showed prolonged hyper-enhancement or iso-enhancement during the portal and late phases on CEUS, making them easily distinguishable from HCC(AFP-). Some EAML lesions (41.7%) were hypo-echoic, similar to HCC(AFP-). However, the hypo-enhancement of EAML lesions occurred later than that of HCC(AFP-) lesions. Thus, our findings may be useful in distinguishing among these lesions to improve diagnostic accuracy.

Comparison of CT and contrast-enhanced ultrasound findings in hepatic angiomyolipoma with pathological correlations

OBJECTIVE

To compare imaging findings of CT and contrast-enhanced US (CEUS) in hepatic angiomyolipoma (HAML) and investigate their pathological correlations.

METHODS

Imaging findings and preoperative diagnosis of CT and CEUS were retrospectively compared head to head in 46 patients with 54 histologically proven HAMLs. Correlations between imaging features and preoperative diagnosis with pathological types of HAMLs were analyzed.

RESULTS

Fat was detected in 100% of lipomatous type, 84.6% of mixed type, and 7.1% of myomatous type (p = 0.000) of HAML at unenhanced CT. Well-defined hyper-echogenicity was displayed in 100% of lipomatous type, 88.5% of mixed type, 50% of myomatous type, and 66.7% of angiomatous type of HAMLs at unenhanced US. More arterial hyper-enhancement was noted on CEUS (100%) than on CT (73.1%) in mixed type (p = 0.015) and in lipomatous type (90.9% vs. 9.1%, p = 0.000) of HAMLs. Washout was present in more HAMLs on CT than on CEUS (42.6% vs. 18.5%, p = 0.007). Correct preoperative diagnosis was suggested in more HAMLs of myomatous type on CEUS than on CT (42.9% vs. 0%, p = 0.016) but showed no difference in other types of HAMLs.

CONCLUSION

There are considerable discrepancies between CT and CEUS findings of HAMLs, and the imaging appearance and preoperative diagnosis of HAMLs on CT and CEUS are significantly affected by pathological types of HAMLs.

Clinical Value of Contrast-Enhanced Ultrasound in Diagnosis of Hyperechoic Liver Lesions

Background

The purpose of this study was to investigate the values of contrast-enhanced ultrasound (CEUS) in the diagnosis and differential diagnosis of hyperechoic liver lesions.

Material/Methods

The CEUS findings of 102 patients with hyperechoic liver lesions identified by 2-dimensional ultrasound in the Affiliated Tumor Hospital of Guangxi Medical University were reviewed and analyzed.

Results

A total of 135 lesions were analyzed, of which malignant lesions were found in 72 patients and benign lesions in 63, with a CEUS accuracy rate of 91.11%, which was significantly higher than that of conventional ultrasound (74.81%; P<0.05).

Conclusions

CEUS can improve the accuracy rate of ultrasonography in the diagnosis and differential diagnosis of hyperechoic liver lesions.

Diagnosis of Hepatic Angiomyolipoma by Combination of Baseline and Contrast-Enhanced Ultrasound--A Prospective Study in Non-Cirrhotic Patients

Objectives

Hepatic angiomyolipoma (HAML) is a rare, benign mesenchymal tumor of the liver and its diagnosis has been considered challenging. The aim of this study was to investigate prospectively the diagnostic efficacy of the incorporation of both baseline ultrasound (US) and contrast-enhanced ultrasound (CEUS) features of HAML in patients without cirrhosis.

Materials and Methods

Consecutive 1748 non-cirrhotic patients with focal liver lesions (FLLs) were prospectively enrolled. Baseline US and CEUS were performed before resection or biopsy. Ultrasound imaging diagnosis of FLLs was compared with the pathological results.

Results

Final diagnoses were established in 41 patients with HAML (2.3%) with normal alpha fetal protein (AFP) level and in 1707 patients with FLL other than HAML. Diagnostic criteria for HAML was based on the combination of baseline US and CEUS appearance of the nodule: (1) Well-defined, marked hyper-echoic nodule without surrounding hypo-echoic halo on baseline US; (2) hyper-enhancement in the arterial phase (exclude initial peripheral nodular enhancement and spoke-wheel arteries) and remains hyper-enhancement or iso-enhancement in the late phase. The diagnostic criteria were fulfilled in 31 HAMLs, 1 hepatocellular adenoma and 1 hemangioma. Ten HAMLs were misdiagnosed as other liver tumors because they did not meet the diagnostic criteria mentioned above and consequently yielded a sensitivity, specificity, positive predictive values, negative predictive values and Youden index of 75.61%, 99.88%, 93.94%, 99.42%, and 0.75 respectively.

Conclusion

The combination of baseline US and CEUS may lead to the correct diagnosis noninvasively in the majority of HAMLs in non-cirrhotic patients with normal AFP level.

Hepatocellular carcinoma with concomitant hepatic angiomyolipoma and cavernous hemangioma in one patient

The risk of developing hepatocellular carcinoma (HCC) is strongly associated with hepatitis B virus infection. Hepatic angiomyolipoma (AML), a rare benign tumor, is composed of a heterogeneous mixture of adipose cells, smooth muscle cells and blood vessels. Here, we report the case of a 44-year-old man who developed HCC with a concomitant hepatic AML and a cavernous hemangioma, in the absence of cirrhosis. To our knowledge, based on an extensive literature search using the www.pubmed.gov website, this is the first report of an HCC case with both concomitant AML and cavernous hemangioma at the same position in the liver. The presence of the hepatitis B surface antigen was detected, but the liver function was normal. Clinical and pathological data were collected before and during the treatment. Hepatic AML was diagnosed based on the typical histological characteristics and immunohistochemical staining, which revealed, a positive staining with a melanocytic cell-specific monoclonal antibody. There was no evidence of tuberous sclerosis complex in this patient. Although the HCC was poor- to moderately-differentiated, the characteristics of the AML and the cavernous hemangioma in this patient did not match any criteria for malignancy. Hepatectomy followed by transarterial chemoembolization treatment were effective therapeutic methods for the adjacent lesions in this patient. This case is an interesting coincidence.

Current consensus and guidelines of contrast enhanced ultrasound for the characterization of focal liver lesions

The application of ultrasound contrast agents (UCAs) is considered essential when evaluating focal liver lesions (FLLs) using ultrasonography (US). Microbubble UCAs are easy to use and robust; their use poses no risk of nephrotoxicity and requires no ionizing radiation. The unique features of contrast enhanced US (CEUS) are not only noninvasiveness but also real-time assessing of liver perfusion throughout the vascular phases. The later feature has led to dramatic improvement in the diagnostic accuracy of US for detection and characterization of FLLs as well as the guidance to therapeutic procedures and evaluation of response to treatment. This article describes the current consensus and guidelines for the use of UCAs for the FLLs that are commonly encountered in US. After a brief description of the bases of different CEUS techniques, contrast-enhancement patterns of different types of benign and malignant FLLs and other clinical applications are described and discussed on the basis of our experience and the literature data.

Contrast-enhanced ultrasound in abdominal imaging

The administration of a contrast agent is considered an essential tool to evaluate abdominal diseases using Ultrasound. The most targeted organ is the liver, especially to characterize focal liver lesions and to assess the response to percutaneous treatment. However, the expanding abdominal indications of contrast-enhanced ultrasound make this technique an important tool in the assessment of organ perfusion including the evaluation of ischemic, traumatic, and inflammatory diseases.

Hepatic angiomyolipoma: diagnostic findings and management

Angiomyolipoma (AML) is a benign mesenchymal tumor that is frequently found in the kidney and, rarely, in the liver. The natural history of hepatic AML has not been clarified, and, because of the similar patterns in imaging studies, such as ultrasonography, computed tomography, and magnetic resonance imaging, some of these tumors have been overdiagnosed as hepatocellular carcinoma in the past. With an increase in the number of case reports showing detailed imaging studies and immunohistochemical staining of the tumor with human melanoma black-45, the diagnostic accuracy is also increasing. In this paper, we focused on the role of noninvasive imaging studies and histological diagnosis showing distinctive characteristics of this tumor. In addition, because several reports have described tumor progression in terms of size, recurrence after surgical resection, metastasis to other organs, and portal thrombosis, we summarized these cases for the management and discussed the indications for the surgical treatment of this tumor.

Preoperative radiological characterization of hepatic angiomyolipoma using magnetic resonance imaging and contrast-enhanced ultrasonography: a case report

Introduction

A hepatic angiomyolipoma is a rare benign tumor of the liver composed of a mixture of smooth muscle cells, blood vessels and a variable amount of adipose tissue. Differentiating them from malignant liver tumors can often be very difficult.

Case presentation

We report the case of a 43-year-old Caucasian man presenting with a large liver mass in the right lobe. The results of magnetic resonance imaging and contrast-enhanced ultrasonography were consistent with a well-demarcated adipose tissue- containing tumor, showing prolonged hyperperfusion in comparison with the surrounding liver tissue. Surgery was performed and the diagnosis of hepatic angiomyolipoma was made with histopathology.

Conclusion

Preoperative radiological characterization using magnetic resonance imaging and contrast-enhanced ultrasonography may improve diagnostic accuracy of hepatic angiomyolipoma. Identification of smooth muscle cells, blood vessels and adipose tissue with a positive immunohistochemical reaction for HMB-45 is the final evidence for an angiomyolipoma.