Hepatocellular adenoma: findings at state-of-the-art magnetic resonance imaging, ultrasound, computed tomography and pathologic analysis

Role of sex in liver tumor occurrence and clinical outcomes: A comprehensive review

Clinical research on sex-based differences in the manifestations, pathophysiology, and prevalence of several diseases, including those affecting the liver, has expanded considerably in recent years. Increasing evidence suggests that liver diseases develop, progress, and respond to treatment differently depending on the sex. These observations support the concept that the liver is a sexually dimorphic organ in which estrogen and androgen receptors are present, which results in disparities between men and women in liver gene expression patterns, immune responses, and the progression of liver damage, including the propensity to develop liver malignancies. Sex hormones play protective or deleterious roles depending on the patient's sex, the severity of the underlying disease, and the nature of precipitating factors. Moreover, obesity, alcohol consumption, and active smoking, as well as social determinants of liver diseases leading to sex-related inequalities, may interact strongly with hormone-related mechanisms of liver damage. Drug-induced liver injury, viral hepatitis, and metabolic liver diseases are influenced by the status of sex hormones. Available data on the roles of sex hormones and gender differences in liver tumor occurrence and clinical outcomes are conflicting. Here, we critically review the main gender-based differences in the molecular mechanisms associated with liver carcinogenesis and the prevalence, prognosis, and treatment of primary and metastatic liver tumors.

Pedunculated Focal Nodular Hyperplasia: When in Doubt, Should We Cut It Out?

Focal nodular hyperplasia (FNH) is the second most common benign hepatic tumor and can rarely present as an exophytic solitary mass attached to the liver by a stalk. Most FNH cases are usually detected as incidental findings during surgery, imaging or physical examination and have a high female predominance. However, the pedunculated forms of FNH are particularly rare and commonly associated with severe complications and diagnostic challenges. Hence, our study aims to provide a comprehensive summary of the available data on the pedunculated FNH cases among adults and children. Furthermore, we will highlight the role of different therapeutic options in treating this clinical entity. The use of imaging techniques is considered a significant addition to the diagnostic toolbox. Regarding the optimal treatment strategy, the main indications for surgery were the presence of symptoms, diagnostic uncertainty and increased risk of complications, based on the current literature. Herein, we also propose a management algorithm for patients with suspected FNH lesions. Therefore, a high index of suspicion and awareness of this pathology and its life-threatening complications, as an uncommon etiology of acute abdomen, is of utmost importance in order to achieve better clinical outcomes.

An Extreme Case of Liver Adenomatosis: Are They All the Same?

Hepatocellular adenoma (HCA) is a rare and benign liver tumor that affects predominantly young and middle-aged women, especially between 30–40 years old. Liver adenomatosis (LA) is defined as the presence of 10 or more HCA. There are authors that report eight different subtypes of HCA, that correlates with clinical and histopathological features, being the inflammatory subtype the most common. We present a case of a 32-year-old Caucasian woman with a history of self-limited episodes of right abdominal pain and an abdominal ultrasound with multiple hypoechogenic liver nodules, suspected of metastasis. She was taking combined oral contraceptive for 6 years. Magnetic Resonance Imaging (MRI) disclosed around 40 nodules, suggestive of HCA. Liver biopsy confirmed HCA, inflammatory subtype. Oral contraceptive was stopped and control MRI 6 months later disclosed reduction of nodules’ dimensions. Management of patients with LA should be based on the size of the largest tumor, as clinical presentation and risk of bleeding or malignancy do not differ between patients with single or multiple HCAs. However, even with biopsy, there is a risk of missampling, raising concern about the real risk of bleeding and malignant potential in patients with different subtypes coexisting in the same liver.

Benign Liver Tumors

Background

Due to the frequent use of medical imaging including ultrasonography, the incidence of benign liver tumors has increased. There is a large variety of different solid benign liver tumors, of which hemangioma, focal nodular hyperplasia (FNH), and hepatocellular adenoma (HCA) are the most frequent. Advanced imaging techniques allow precise diagnosis in most of the patients, which reduces the need for biopsies only to limited cases. Patients with benign liver tumors are mostly asymptomatic and do not need any kind of treatment. Symptoms can be abdominal pain and pressure effects on adjacent structures. The 2 most serious complications are bleeding and malignant transformation.

Summary

This review focuses on hepatic hemangioma (HH), FNH, and HCA, and provides an overview on clinical presentations, surgical and interventional treatment, as well as conservative management. Treatment options for HHs, if indicated, include liver resection, radiofrequency ablation, and transarterial catheter embolization, and should be carefully weighed against possible complications. FNH is the most frequent benign liver tumor without any risk of malignant transformation, and treatment should only be restricted to symptomatic patients. HCA is associated with the use of oral contraceptives or other steroid medications. Unlike other benign liver tumors, HCA may be complicated by malignant transformation. HCAs have been divided into 6 subtypes based on molecular and pathological features with different risk of complication.

Key Message

The vast majority of benign liver tumors remain asymptomatic, do not increase in size, and rarely need treatment. Biopsies are usually not needed as accurate diagnosis can be obtained using modern imaging techniques.

Contrast-enhanced ultrasound patterns of hepatocellular adenoma: an Italian multicenter experience

PURPOSE

Hepatocellular adenoma (HCA) is a rare benign monoclonal neoplasm, recently categorized on genetic and histopathological basis into four subtypes with different biological behaviors. Since contrast-enhanced ultrasonography (CEUS) is nowadays a well-established technique for liver nodule characterization, the aim of our study was to assess CEUS features of HCAs to identify criteria that correlate with different HCA subtypes as compared to histopathologic examination and other imaging modalities.

METHODS

We retrospectively analyzed data of patients with histology-proven HCA who underwent CEUS, computed tomography or magnetic resonance imaging (MRI) in seven different Italian ultrasound units.

RESULTS

The study enrolled 19 patients (16 females; 69% with concomitant/prior use of oral contraceptives): the mean size of all HCAs was 4.2 cm (range 1.6-7.1 cm); 14/19 had inflammatory HCAs (I-HCA), 1/19 β-catenin-activated HCA, and the others unclassified HCAs. On CEUS, during the arterial phase, all but one HCA displayed a rapid enhancement, with 89% of these showing centripetal and 11% centrifugal filling pattern, whereas during the portal and late venous phase 58% of HCA showed washout and the remaining 42% displayed persistent enhancement. In particular, among I-HCAs 7/14 showed no washout, 3/14 and 4/14 showed washout in the portal or late phase, respectively.

CONCLUSIONS

This dataset represents one of the few published experiences on HCAs and CEUS in Italy and shows that HCAs are hypervascularized in the arterial phase usually with a centripetal flow pattern and have a heterogeneous behavior in portal and late phase. In particular, occurrence of delayed washout on CEUS but not on MRI is frequently observed in the subtype of I-HCA.

Hepatocellular adenoma: An unsolved diagnostic enigma

Hepatocellular adenoma (HCA) is a rare benign liver tumour associated with the use of oral contraceptives or other steroid medications which occurs predominantly in young and middle-aged women. Unlike other benign liver tumours, an HCA may be complicated by bleeding and malignant transformation. HCAs have been divided into four subtypes based on molecular and pathological features: hepatocyte nuclear factor 1α-mutated HCA, inflammatory HCA, β-catenin-mutated HCA, and unclassified HCA. β-catenin-mutated HCA has the highest risk of haemorrhage or malignant transformation. In the latest upgrade of the guidelines regarding the management of benign liver tumours published in 2016 by the European Association for the Study of the Liver, magnetic resonance imaging (MRI) was recognized to be superior to all other imaging modalities in detecting HCAs and in being able to subtype HCAs up to 80%, with positive identification of 1α-mutated HCA or inflammatory HCA achievable with > 90% specificity. This review analyzed the imaging features of HCA using MRI with hepato-specific contrast agents, focusing on the limitations in the HCA characterization.

Evaluation of texture analysis for the differential diagnosis of focal nodular hyperplasia from hepatocellular adenoma on contrast-enhanced CT images

PURPOSE

To explore the value of CT texture analysis (CTTA) for differentiation of focal nodular hyperplasia (FNH) from hepatocellular adenoma (HCA) on contrast-enhanced CT (CECT).

METHODS

This is a retrospective, IRB-approved study conducted in a single institution. A search of the medical records between 2008 and 2017 revealed 48 patients with 70 HCA and 50 patients with 62 FNH. All lesions were histologically proven and with available pre-operative CECT imaging. Hepatic arterial phase (HAP) and portal venous phase (PVP) were used for CTTA. Textural features were extracted using a commercially available research software (TexRAD). The differences between textural parameters of FNH and HCA were assessed using the Mann-Whitney U test and the AUROC were calculated. CTTA parameters showing significant difference in rank sum test were used for binary logistic regression analysis. A p value < 0.05 was considered statistically significant.

RESULTS

On HAP images, mean, mpp, and skewness were significantly higher in FNH than in HCA on unfiltered images (p ≤ 0.007); SD, entropy, and mpp on filtered analysis (p ≤ 0.006). On PVP, mean, mpp, and skewness in FNH were significantly different from HCA (p ≤ 0.001) on unfiltered images, while entropy and kurtosis were significantly higher in FNH on filtered images (p ≤ 0.018). The multivariate logistic regression analysis indicated that the mean, mpp, and entropy of medium-level and coarse-level filtered images on HAP were independent predictors for the diagnosis of HCA and a model based on all these parameters showed the largest AUROC (0.824).

CONCLUSIONS

Multiple explored CTTA parameters are significantly different between FNH and HCA on CECT.

Liver Masses: What Physicians Need to Know About Ordering and Interpreting Liver Imaging

PURPOSE OF REVIEW

This paper reviews diagnostic imaging techniques used to characterize liver masses and the imaging characteristics of the most common liver masses.

RECENT FINDINGS

The role of recently adopted ultrasound and magnetic resonance imaging contrast agents will be emphasized. Contrast-enhanced ultrasound is an inexpensive exam which can confirm benignity of certain liver masses without ionizing radiation. Magnetic resonance imaging using hepatocyte-specific gadolinium-based contrast agents can help confirm or narrow the differential diagnosis of liver masses.

Hepatocellular adenoma: when and how to treat? Update of current evidence

Hepatocellular adenoma (HCA) is a rare, benign liver tumor. Discovery of this tumor is usually as an incidental finding, correlated with the use of oral contraceptives, or pregnancy. Treatment options have focused on conservative management for the straightforward, smaller lesions (<5 cm), with resection preferred for larger lesions (>5 cm) that pose a greater risk of hemorrhage or malignant progression. In recent years, a new molecular subclassification of HCA has been proposed, associated with characteristic morphological features and loss or increased expression of immunohistochemical markers. This subclassification could possibly provide considerable benefits in terms of patient stratification, and the selection of treatment options. In this review we discuss the decision-making processes and associated risk analyses that should be made based on lesion size, and subtype. The usefulness of this subclassification system in terms of the procedures instigated as part of the diagnostic work-up of a suspected HCA will be outlined, and suitable treatment schemes proposed.

Hepatocellular adenoma: comparison between real-time contrast-enhanced ultrasound and dynamic computed tomography

Purpose

To investigate and compare the contrast-enhanced ultrasound (CEUS) features of histologically proven HCA with those of contrast-enhanced computed tomography (CECT).

Methods

Eighteen patients with proven hepatic adenoma by pathology were retrospectively selected from the CEUS database. Fourteen of them had undergone liver CECT exams. The basic features on unenhanced imaging and the enhancement level and specific features on contrast-enhanced imaging were retrospectively analyzed, and the differences between CEUS and CECT were compared.

Results

All the HCAs showed hyper-enhancement in the arterial phase. During the portal and late phases, 12 HCAs (12/18, 66.7 %) on CEUS and 11 (11/14, 78.6 %) on CT showed washout. On CEUS, 10 (10/18, 55.5 %) showed centripetal filling in the arterial phase and persistent peripheral rim enhancement. Five of them (61.1 %, 11/18) showed delayed central washout in the portal or late phase. However, on CECT, 2 (14.3 %, 2/14) and 4 (28.6 %, 4/14) HCAs showed persistent enhancement of the peripheral rim and central non-enhancing hemorrhage areas, respectively.

Conclusions

Compared with dynamic CT, CEUS was superior at characterizing specific dynamic features. Considering that it is radiation-free, readily availability and easy to use, CEUS is suggested as the first line imaging tool to diagnose HCA.

[The efficacy of endoscopic endosonography in diagnosis of benign and malignant stenoses of common bile duct]

AIM

To define criteria and to estimate diagnostic significance of endosonography in differential diagnosis of benign and malignant stenoses of common bile duct.

MATERIAL AND METHODS

We presented the results of survey and treatment of 57 patients with benign and malignant stenoses of common bile duct. The technique of endosonography is described. We have formulated major criteria of differential diagnostics of tumoral and non-tumoral lesion of extrahepatic bile ducts. Comparative analysis of endosonography, ultrasound, computed tomography and magnetic resonance cholangiopancreatography was performed.

RESULTS

Sensitivity, specificity and accuracy of endosonography in diagnosis of stenosis cause is 97.7%, 100% and 98.2% respectively. So it exceeds the efficacy of other diagnostic X-ray methods. In modern surgical clinic endosonography should be mandatory performed. It is necessary for final diagnostics of cause of common bile duct stenosis especially in case of its low location.

Ultrasound features of hepatocellular adenoma and the additional value of contrast-enhanced ultrasound

BACKGROUND

Hepatocellular adenoma (HCA) is a rare benign tumor of the liver. It is of clinical importance to differentiate HCA from other liver tumors, especially hepatocellular carcinoma (HCC). This study aimed to evaluate the characteristic features of HCA by conventional ultrasound and contrast-enhanced ultrasound (CEUS) findings.

METHODS

Twenty-six patients (10 males and 16 females; mean age 36.2+/-5.0 years) with 26 histopathologically proven HCAs were retrospectively identified. According to the maximum diameter of HCAs, they were divided into three groups: <30 mm, 30-50 mm, and >50 mm. Ultrasound examinations were performed with C5-2 broadband curved transducer of Philips iU22 unit (Philips Bothell, WA, USA). For each lesion, a dose of 2.4 mL SonoVue® (Bracco Imaging Spa, Milan, Italy) was injected as a quick bolus into the cubital vein. Lesions' echogenicity, color-Doppler flow imaging and contrast enhancement patterns were recorded.

RESULTS

Grayscale ultrasound revealed that most of HCAs were hypoechoic (73.1%, 19/26). Spotty calcifications were detected in 26.9% (7/26) of the lesions. Color-Doppler flow imaging detected centripetal bulky color flow in 46.2% (12/26) of the HCAs. CEUS showed that 73.1% (19/26) of the HCAs displayed as rapid, complete and homogenous enhancement, and 53.8% (14/26) showed decreased contrast enhancement in the late phase. There was no significant difference in enhancement patterns among different sizes of HCAs (P>0.05). Centripetal enhancement with subcapsular tortuous arteries was common in larger HCAs.

CONCLUSIONS

CEUS combined with grayscale and color-Doppler flow imaging helped to improve preoperative diagnosis of HCAs. The characteristic imaging features of HCAs included: rapid homogeneous enhancement and slow wash-out pattern on CEUS; heterogeneous echogenicity on grayscale ultrasound; and centripetal enhancement with subcapsular tortuous arteries in large HCAs.

Benign liver tumors in pediatric patients - Review with emphasis on imaging features

Benign hepatic tumors are commonly observed in adults, but rarely reported in children. The reasons for this remain speculative and the exact data concerning the incidence of these lesions are lacking. Benign hepatic tumors represent a diverse group of epithelial and mesenchymal tumors. In pediatric patients, most benign focal liver lesions are inborn and may grow like the rest of the body. Knowledge of pediatric liver diseases and their imaging appearances is essential in order to make an appropriate differential diagnosis. Selection of the appropriate imaging test is challenging, since it depends on a number of age-related factors. This paper will discuss the most frequently encountered benign liver tumors in children (infantile hepatic hemangioendothelioma, mesenchymal hamartoma, focal nodular hyperplasia, nodular regenerative hyperplasia, and hepatocellular adenoma), as well as a comparison to the current knowledge regarding such tumors in adult patients. The current emphasis is on imaging features, which are helpful not only for the initial diagnosis, but also for pre- and post-treatment evaluation and follow-up. In addition, future perspectives of contrast-enhanced ultrasound (CEUS) in pediatric patients are highlighted, with descriptions of enhancement patterns for each lesion being discussed. The role of advanced imaging tests such as CEUS and magnetic resonance imaging, which allow for non-invasive assessment of liver tumors, is of utmost importance in pediatric patients, especially when repeated imaging tests are needed and radiation exposure should be avoided.

Genotype-phenotype correlations in hepatocellular adenoma: an update of MRI findings

Hepatocellular adenoma (HCA) is a generally benign liver tumor with the potential for malignancy and bleeding. HCAs are categorized into four subtypes on the basis of genetic and pathological features: hepatocyte nuclear factor 1α-mutated HCA, β-catenin-mutated HCA, inflammatory HCA, and unclassified HCA. Magnetic resonance imaging (MRI) plays an important role in the diagnosis, subtype characterization, and detection of HCA complications; it is also used to differentiate HCA from focal nodular hyperplasia. In this review, we present an overview of the genetic abnormalities, oncogenesis, and typical and atypical MRI findings of specific subtypes of HCA using contrast-enhanced MRI with or without hepatobiliary contrast agents (gadobenate dimeglumine and gadoxetate disodium). We also discuss their different management implications after diagnosis.

A triple stain of reticulin, glypican-3, and glutamine synthetase: a useful aid in the diagnosis of liver lesions

CONTEXT

The correct histologic diagnosis of mass lesions of the liver can be difficult, especially in biopsy samples. Reticulin, glypican-3, and glutamine synthetae are stains that can help distinguish hepatocellular carcinoma, hepatic adenoma, and focal nodular hyperplasia.

OBJECTIVE

To evaluate the utility of a triple stain of reticulin, glypican-3, and glutamine synthetae in distinguishing hepatocellular carcinoma, hepatic adenoma, and focal nodular hyperplasia.

DESIGN

Whole tissue sections and tissue microarrays were evaluated with a triple stain of reticulin, followed by glutamine synthetae (diaminobenzidine, brown chromogen) and glypican-3 (alkaline phosphatase, red chromogen). The 109 cases evaluated included whole tissue section hepatocellular carcinoma (n = 16), tissue microarray hepatocellular carcinoma (n = 19), whole tissue section hepatic adenoma (n = 15), tissue microarray hepatic adenoma (n = 13), whole tissue section focal nodular hyperplasia (n = 13; 12%), tissue microarray focal nodular hyperplasia (n = 13), as well as nonmalignant liver parenchyma adjacent to hepatocellular carcinoma (n = 20). All cases were scored for reticulin being intact or lost, positive or negative staining for glypican-3, and diffuse, maplike, perivenular, or negative staining for glutamine synthetae.

RESULTS

The combination of intact reticulin with either glypican-3 negativity or negative glutamine synthetae was 92% sensitive and 95% specific in the distinction of tissue microarray hepatic adenoma from hepatocellular carcinoma. For the distinction of tissue microarray focal nodular hyperplasia and hepatic adenoma, maplike glutamine synthetae was most useful and was 85% sensitive and 100% specific.

CONCLUSIONS

The triple stain of reticulin, glypican-3, and glutamine synthetae is useful in the differentiation of hepatocellular carcinoma, hepatic adenoma, and focal nodular hyperplasia on biopsy specimens. Furthermore, this triple stain is advantageous to single stains and can help when aberrant staining patterns are observed.

Testosterone-receptor positive hepatocellular carcinoma in a 29-year old bodybuilder with a history of anabolic androgenic steroid abuse: a case report

Background

Continuous use of anabolic androgenic steroid in high-doses is associated with substantial health risks, including hepatocellular adenoma. Malignant transformation from hepatocellular adenoma to hepatocellular carcinoma after anabolic androgenic steroid abuse has been rarely reported. The morphological distinction of adenoma from well-differentiated hepatocellular carcinoma is challenging and requires elaborated imaging techniques and histology.

Case presentation

We report about a 29-year old male professional bodybuilder who presented with mid-epigastric pain at the emergency unit. Ultrasound showed a severe hepatomegaly with multiple lesions. Contrast-enhanced ultrasound revealed a heterogeneous pattern with signs of hepatocellular carcinoma. CT scan of the abdomen confirmed multiple hypervascular lesions and central areas of necrosis without contrast enhancement. Subsequent diagnostics included fine needle aspiration (FNA) of suspicious lesions and mini-laparoscopy to establish the diagnosis of a β-catenin and testosterone-receptor positive hepatocellular carcinoma embedded in multiple adenomas. The patient was subsequently treated by liver transplantation and remains tumor-free 27 month after surgery.

Conclusion

Hepatocellular carcinoma occurring in association with anabolic androgenic steroid abuse should sensitize physicians and especially professional bodybuilders for the harmful use of high doses of steroids.

Current updates on the molecular genetics and magnetic resonance imaging of focal nodular hyperplasia and hepatocellular adenoma

Focal nodular hyperplasia (FNH) and hepatocellular adenomas (HCAs) constitute benign hepatic neoplasms in adults. HCAs are monoclonal neoplasms characterised by an increased predilection to haemorrhage and also malignant transformation. On the other hand, FNH is a polyclonal tumour-like lesion that occurs in response to increased perfusion and has an uneventful clinical course. Recent advances in molecular genetics and genotype-phenotype correlation in these hepatocellular neoplasms have enabled a new classification system. FNHs are classified into the typical and atypical types based on histomorphological and imaging features. HCAs have been categorised into four subtypes: (1) HCAs with HNF-1α mutations are diffusely steatotic, do not undergo malignant transformation, and are associated with familial diabetes or adenomatosis. (2) Inflammatory HCAs are hypervascular with marked peliosis and a tendency to bleed. They are associated with obesity, alcohol and hepatic steatosis. (3) HCAs with β-catenin mutations are associated with male hormone administration and glycogen storage disease, frequently undergo malignant transformation and may simulate hepatocellular carcinoma on imaging. (4) The final type is unclassified HCAs. Each of these except the unclassified subtype has a few distinct imaging features, often enabling reasonably accurate diagnosis. Biopsy with immunohistochemical analysis is helpful in difficult cases and has strong implications for patient management.

TEACHING POINTS

• FNHs are benign polyclonal neoplasms with no risk of haemorrhage or malignancy. • HCAs are benign monoclonal neoplasms classified into four subtypes based on immunohistochemistry. • Inflammatory HCAs show an atoll sign with a risk of bleeding and malignant transformation. • HNF-1α HCAs are steatotic HCAs with minimal complications and the best prognosis. • β-Catenin HCA shows variable MRI features and a high risk of malignancy.

Gadoxetic acid enhanced MRI for differentiation of FNH and HCA: a single centre experience

OBJECTIVES

Evaluation of enhancement characteristics of histopathologically confirmed focal nodular hyperplasias (FNHs) and hepatocellular adenomas (HCAs) with gadoxetic acid-enhanced MRI.

METHODS

Sixty-eight patients with 115 histopathologically proven lesions (FNHs, n=44; HCAs, n=71) examined with gadoxetic acid-enhanced MRI were retrospectively enrolled (standard of reference: surgical resection, n=53 patients (lesions: FNHs, n=37; HCAs, n=53); biopsy, n=15 (lesions: FNHs, n=7; HCAs, n=18)). Two radiologists evaluated all MR images regarding morphological features as well as the vascular and hepatocyte-specific enhancement in consensus.

RESULTS

For the hepatobiliary phase, relative enhancement of the lesions and lesion to liver enhancement were significantly lower for HCAs (mean, 48.7 (±48.4)%and 49.4 (±33.9) %) compared to FNHs (159.3 (±92.5) %; and 151.7 (±79) %; accuracy of 89%and 90 %, respectively; P<0.001). Visual strong uptake of FNHs vs. hypointensity of HCAs in the hepatobiliary phase resulted in an accuracy of 92 %. This parameter was superior to all other morphological and dynamic vascular criteria alone and in combination (accuracy, 54–85 %).

CONCLUSIONS

For differentiation of FNHs and HCAs by means of MRI, gadoxetic acid uptake in the hepatobiliary phase was found to be superior to all other criteria alone and in combination.

KEY POINTS

EOB-MRI is well suited to differentiate FNHs and hepatocellular adenomas. For this purpose hepatobiliary phase is superior to unenhanced and dynamic imaging. Hepatobiliary phase (peripheral) hyper- or isointensity is typical for FNH. Hepatobiliary phase hypointensity is typical for hepatocellular adenomas. EOB-MRI helps to avoid misinterpretations of benign hepatocellular lesions.

Liver masses: a clinical, radiologic, and pathologic perspective

Liver masses present a relatively common clinical dilemma, particularly with the increasing use of various imaging modalities in the diagnosis of abdominal and other symptoms. The accurate and reliable determination of the nature of the liver mass is critical, not only to reassure individuals with benign lesions but also, and perhaps more importantly, to ensure that malignant lesions are diagnosed correctly. This avoids the devastating consequences of missed diagnosis and the delayed treatment of malignancy or the unnecessary treatment of benign lesions. With appropriate interpretation of the clinical history and physical examination, and the judicious use of laboratory and imaging studies, the majority of liver masses can be characterized noninvasively. Accurate characterization of liver masses by cross-sectional imaging is particularly dependent on an understanding of the unique phasic vascular perfusion of the liver and the characteristic behaviors of different lesions during multiphasic contrast imaging. When noninvasive characterization is indeterminate, a liver biopsy may be necessary for definitive diagnosis. Standard histologic examination usually is complemented by immunohistochemical analysis of protein biomarkers. Accurate diagnosis allows the appropriate selection of optimal management, which is frequently reassurance or intermittent follow-up evaluations for benign masses. For malignant lesions or those at risk of malignant transformation, management depends on the tumor staging, the functional status of the uninvolved liver, and technical surgical considerations. Unresectable metastatic masses require oncologic consultation and therapy. The efficient characterization and management of liver masses therefore requires a multidisciplinary collaboration between the gastroenterologist/hepatologist, radiologist, pathologist, hepatobiliary or transplant surgeon, and medical oncologist.

Inflammatory hepatocellular adenomas can mimic focal nodular hyperplasia on gadoxetic acid-enhanced MRI

OBJECTIVE

Inflammatory hepatocellular adenoma (HCA) is a recently categorized entity of hepatocellular neoplasms. We investigated whether gadoxetic acid-enhanced MRI can distinguish inflammatory HCA from focal nodular hyperplasia (FNH).

MATERIALS AND METHODS

From January 1, 2009, through January 1, 2013, gadoxetic acid-enhanced MRI examinations from two institutions were reviewed for HCA, with specific histologic features of inflammatory HCA. Biopsy and resection slides were reviewed, and immunohistochemistry for glutamine synthetase was performed in a subset to confirm the initial diagnosis.

RESULTS

A total of 10 possible cases of inflammatory HCA were identified in the pathology database. On the basis of glutamine synthetase staining performed for this study, three cases were rediagnosed as FNH and thus were excluded from the study. Therefore, a total of seven patients with inflammatory HCA were identified. On gadoxetic acid-enhanced MRI, four of these patients had classic features of FNH (group A, FNH mimics), and three had imaging features suggestive of HCA (group B, typical inflammatory HCA). Imaging features that were considered diagnostic of FNH included isointense or minimal T2 hyperintensity, arterial enhancement, and diffuse hyperintensity on hepatobiliary phase. Three of the four patients with FNH mimics had slides available for pathologic rereview, and the diagnosis of inflammatory HCA was supported by glutamine synthetase immunohistochemistry findings. The pathology reports of the remaining four cases were rereviewed and were also found to have features consistent with inflammatory HCA.

CONCLUSION

Inflammatory HCA can mimic FNH on MRI, including hepatobiliary phase hyperintensity. Moreover, conventional pathology using histopathology alone may lead to misclassification of inflammatory HCA.

Application of dual phase imaging of 11C-acetate positron emission tomography on differential diagnosis of small hepatic lesions

Objective

Previously we observed that dual phase ¹¹C-acetate positron emission tomography (AC-PET) could be employed for differential diagnosis of liver malignancies. In this study, we prospectively evaluated the effect of dual phase AC-PET on differential diagnosis of primary hepatic lesions of 1–3 cm in size.

Methods

33 patients having primary hepatic lesions with size of 1–3 cm in diameter undertook dual phase AC-PET scans. Procedure included an early upper-abdomen scan immediately after tracer injection and a conventional scan in 11–18 min. The standardized uptake value (SUV) was calculated for tumor (SUVT) and normal tissue (SUVB), from which ¹¹C-acetate uptake ratio (as lesion against normal liver tissue, SUVT/SUVB) in early imaging (R1), conventional imaging (R2), and variance between R2 and R1 (ΔR) were derived. Diagnoses based on AC-PET data and histology were compared. Statistical analysis was performed with SPSS 19.0.

Results

20 patients were found to have HCC and 13 patients had benign tumors. Using ΔR>0 as criterion for malignancy, the accuracy and specificity were significantly increased comparing with conventional method. The area under ROC curve (AUC) for R1, R2, and ΔR were 0.417, 0.683 and 0.831 respectively. Differential diagnosis between well-differentiated HCCs and benign lesions of FNHs and hemangiomas achieved 100% correct. Strong positive correlation was also found between R1 and R2 in HCC (r² = 0.55, P<0.001).

Conclusions

Dual phase AC-PET scan is a useful procedure for differential diagnosis of well-differentiated hepatocellular carcinoma and benign lesions. The dynamic changes of ¹¹C-acetate uptake in dual phase imaging provided key information for final diagnosis.

Acute nontraumatic liver lesions

The principal conditions requiring emergency/urgent intervention in patients with nontraumatic liver lesions are hemorrhage (with or without tumor rupture), rupture of hydatid cysts (with or without infection), complications arising from liver abscesses or congenital liver cysts, rupture related to peliosis hepatis, and in rare cases spontaneous hemorrhage. This article examines each of these conditions, its appearance on ultrasound (the first-line imaging method of choice for assessing any urgent nontraumatic liver lesion) and indications for additional imaging studies.

Imaging of multifocal hepatic lesions in pediatric patients

Imaging plays a vital role in detection and characterization of multifocal liver lesions in children. Numerous causes for these lesions exist, including benign and malignant neoplasms, infectious lesions, and congenital and inflammatory conditions. The imaging spectrum of multifocal liver lesions in children is presented with emphasis on key imaging features, differential diagnoses and helpful relevant clinical features.

That liver lesion on MDCT in the oncology patient: is it important?

Multidetector-row computed tomography (MDCT) has become the primary imaging test for the staging and follow-up of most malignancies that originate outside of the central nervous system. Technical advances in this imaging technique have led to significant improvement in the detection of metastatic disease to the liver. An unintended by-product of this improving diagnostic acumen is the discovery of incidental hepatic lesions in oncology patients that in the past remained undetected. These ubiquitous, incidentally identified hepatic lesions have created a management dilemma for both clinicians and radiologists: are these lesions benign or do they represent metastases? Naturally, the answer to this question has profound prognostic and therapeutic implications. In this review, guidelines concerning the diagnosis and management of some of the more common hepatic incidental lesions detected in patients with extrahepatic malignancies are presented.

Hepatocellular adenoma: evaluation with contrast-enhanced ultrasound and MRI and correlation with pathologic and phenotypic classification in 26 lesions

Purpose. To review the contrast-enhanced ultrasonographic (CEUS) and magnetic resonance (MR) imaging findings in 25 patients with 26 hepatocellular adenomas (HCAs) and to compare imaging features with histopathologic results from resected specimen considering the new immunophenotypical classification. Material and Methods. Two abdominal radiologists reviewed retrospectively CEUS cineloops and MR images in 26 HCA. All pathological specimens were reviewed and classified into four subgroups (steatotic or HNF 1α mutated, inflammatory, atypical or β-catenin mutated, and unspecified). Inflammatory infiltrates were scored, steatosis, and telangiectasia semiquantitatively evaluated. Results. CEUS and MRI features are well correlated: among the 16 inflammatory HCA, 7/16 presented typical imaging features: hypersignal T2, strong arterial enhancement with a centripetal filling, persistent on delayed phase. 6 HCA were classified as steatotic with typical imaging features: a drop out signal, slight arterial enhancement, vanishing on late phase. Four HCA were classified as atypical with an HCC developed in one. Five lesions displayed important steatosis (>50%) without belonging to the HNF1α group. Conclusion. In half cases, inflammatory HCA have specific imaging features well correlated with the amount of telangiectasia and inflammatory infiltrates. An HCA with important amount of steatosis noticed on chemical shift images does not always belong to the HNF1α group.

Systematic review of haemorrhage and rupture of hepatocellular adenomas

BACKGROUND

Although benign in itself, hepatocellular adenoma (HCA) can be complicated by hormone-induced growth, and subsequent haemorrhage and rupture. The exact risk of haemorrhage and rupture is not known. This systematic review of the literature was carried out with the aim of estimating the risk of haemorrhage and rupture in HCA.

METHODS

A systematic literature search of the PubMed and Embase databases was performed for all articles relevant to haemorrhage and/or rupture of HCA, published between 1969 and March 2011.

RESULTS

Twenty-eight articles met the selection criteria, containing a total of 1176 patients. Haemorrhage was reported with an overall frequency of 27·2 per cent among patients, and in 15·8 per cent of all HCA lesions. Rupture and intraperitoneal bleeding were reported in 17·5 per cent of patients. Bleeding was the first symptom in 68·5 per cent of patients with a bleeding HCA. Six of 13 articles reporting the size of HCA lesions in which bleeding occurred mentioned haemorrhage in HCAs smaller than 5 cm.

CONCLUSION

Haemorrhage and rupture are common in patients with HCA.

Appearance of hepatocellular adenomas on gadoxetic acid-enhanced MRI

OBJECTIVE

The purpose of this study was to evaluate enhancement characteristics of hepatocellular adenomas (HCAs) using gadoxetic acid as a hepatocyte-specific MR contrast agent.

METHODS

Twenty-four patients with histopathologically proven HCAs were retrospectively identified. MRI consisted of T1- and T2-weighted (w) sequences with and without fat saturation (fs), multiphase dynamic T1-w images, and fs T1-w images during the hepatobiliary phase. Standard of reference was surgical resection (n = 19) or biopsy (n = 5). Images were analysed for morphology and contrast behaviour including signal intensity (SI) measurement on T1-w images normalised to the pre-contrast base line.

RESULTS

In total 34 HCAs were evaluated. All HCAs showed enhancement in the arterial phase; 38 % of HCAs showed reduced contrast enhancement ("wash-out") in the venous phase. All HCAs showed enhancement (SI increase, 56 ± 53 %; P <0.001) in the hepatobiliary phase, although liver uptake was stronger (96 ± 58 %). Thus, 31 of all HCAs (91 %) appeared hypointense to the surrounding liver in the hepatobiliary phase, while 3 out of 34 lesions were iso-/hyperintense.

CONCLUSIONS

Gadoxetic acid accumulates in HCAs in the hepatobiliary phase, although significantly less than in surrounding liver. Thus, HCA appears in the vast majority of cases as a hypointense lesion on hepatobiliary phase images.

KEY POINTS

• Magnetic resonance-specific contrast agents are now available for hepatic imaging. • Hepatocellular adenomas enhance with gadoxetic acid as in previous CT/MRI experience. • Enhancement during the hepatobiliary phase is less in HCAs than in liver. • Typical HCAs appear as hypointense lesions on T1-w hepatobiliary phase images. • True hyperintense HCA enhancement can occasionally occur during the hepatobiliary phase.

Hepatocellular adenoma and focal nodular hyperplasia: value of gadoxetic acid-enhanced MR imaging in differential diagnosis

PURPOSE

To retrospectively evaluate the utility of gadoxetic acid-enhanced magnetic resonance (MR) imaging in the differential diagnosis of hepatocellular adenoma (HCA) and focal nodular hyperplasia (FNH).

MATERIALS AND METHODS

This study had institutional review board approval; the requirement for informed consent was waived. Eighty-two patients (58 patients with FNH and 24 patients with HCAs) with 111 lesions were included in the study. There were 74 female patients and eight male patients (mean age, 41.9 years±13.2 [standard deviation]; age range, 11-78 years). Two readers reviewed all images in terms of signal intensity (SI) features on unenhanced, dynamic, and hepatobiliary phase images. For quantitative analysis, contrast enhancement ratio (CER), lesion-to-liver contrast (LLC), and SI ratio on dynamic and hepatobiliary phase images were calculated.

RESULTS

The CER of FNH in the arterial phase (mean, 94.3%±33.2) was significantly higher than that of HCAs (mean, 59.3%±28.1) (P<.0001). During the hepatobiliary phase, the LLC of FNH showed minimally positive values (mean, 0.05±0.01) and that of HCAs demonstrated strong negative values (mean, -0.67±0.24) (P<.0001). The area under the receiver operating characteristic curve of the hepatobiliary phase SI ratio for differentiation of the two tumors was 0.97, and a sensitivity of 92% and specificity of 91% were found with a cutoff value of 0.87. Among six FNH lesions that showed atypical hypointensity during the hepatobiliary phase, four had a large central scar, one contained a substantial fat component, and one had abundant radiating fibrous septa. Three HCAs were isointense during the hepatobiliary phase owing to severe hepatic steatosis.

CONCLUSION

Gadoxetic acid-enhanced MR imaging facilitates the differentiation of FNH from HCA.

Can a decision-making model be justified in the management of hepatocellular adenoma?

During recent years, there was a great development in the area of hepatocellular adenomas (HCA), especially regarding the pathological subtype classification, radiological imaging and management during pregnancy. This review discusses the current knowledge about diagnosis and treatment modalities of HCA and proposes a decision-making model for HCA. A Medline search of studies relevant to epidemiology, histopathology, complications, imaging and management of HCA lesions was undertaken. References from identified articles were hand-searched for further relevant articles.

Safety and efficacy of radiofrequency ablation for hepatocellular adenoma

PURPOSE

To investigate the safety and efficacy of radiofrequency (RF) ablation for the treatment of hepatocellular adenoma (HCA).

MATERIALS AND METHODS

From 2000 to 2009, 170 patients with HCA were referred to a single tertiary hepatobiliary center. Medical records of 18 patients treated with RF ablation were retrospectively analyzed.

RESULTS

All patients were female, and the majority had a history of hormonal contraceptive use. Ten patients (56%) had multiple HCAs, with a median number of two lesions (range, one to 12) per patient. Median size of HCA at the time of RF ablation was 3.0 cm (range, 0.8-7.3 cm). A total of 45 HCAs were ablated in 32 sessions (open, n = 4; percutaneous, n = 28). RF ablation was complete after the first session in 26 HCAs (57.8%), and the majority of patients underwent multiple RF ablation sessions to fully ablate all HCAs. Major complications developed in two patients.

CONCLUSIONS

RF ablation can be used effectively in the treatment of HCA. However, multiple sessions are often required, and signs of residual adenoma might persist in some patients despite repetitive treatment. RF ablation might be especially beneficial in cases not amenable to surgery or in patients who would require major hepatic resection otherwise.

Hepatocellular adenomas: correlation of MR imaging findings with pathologic subtype classification

PURPOSE

To investigate the correlation between magnetic resonance (MR) imaging findings and pathologic subtype classification of hepatocellular adenoma (HCA).

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board, and the requirement for informed consent was waived. MR imaging studies of 61 lesions (48 patients; median age, 36 years) were available and were independently reviewed by two radiologists. Consensus readings on all morphologic and signal-intensity imaging features were obtained. Previously, these lesions had been classified on the basis of pathologic findings and immunohistochemical analysis. Fisher exact and χ² tests were performed to compare the results between the different subtypes. A Bonferroni correction was applied to correct for multiple testing (α < .0033).

RESULTS

MR imaging signs of diffuse intratumoral fat deposition were present in seven (78%) of nine liver-fatty acid binding protein (L-FABP)-negative HCAs compared with five (17%) of 29 inflammatory HCAs (P = .001). Steatosis within the nontumoral liver was present in 11 (38%) of 29 inflammatory HCAs compared with none of the L-FABP-negative HCAs (P = .038). A characteristic atoll sign was only seen in the inflammatory group (P = .027). Presence of a typical vaguely defined type of scar was seen in five (71%) of seven β-catenin-positive HCAs (P = .003). No specific MR imaging features were identified for the unclassified cases.

CONCLUSION

L-FABP-negative, inflammatory, and β-catenin-positive HCAs were related to MR imaging signs of diffuse intratumoral fat deposition, an atoll sign, and a typical vaguely defined scar, respectively. Since β-catenin-positive HCAs are considered premalignant, closer follow-up with MR imaging or resection may be preferred.

Hepatic incidentalomas

Recent advances in multidetector-row computed tomography, magnetic resonance imaging, and ultrasonography have led to the detection of incidental hepatic lesions in both the oncology and nononcology patient population that in the past remained undiscovered. These incidental hepatic lesions have created a management dilemma for both clinicians and radiologists. In this review, guidelines concerning the diagnosis and management of some of the more common hepatic incidentalomas are presented.

Management of hepatocellular adenoma during pregnancy

BACKGROUND & AIMS

Hepatocellular adenoma in pregnant women requires special considerations because of the risk of hormone induced growth and rupture. To prevent these potential lethal complications, pregnancy is either often discouraged or the surgical resection of large adenomas is recommended. It may be questioned whether it is justified to deny a young woman a pregnancy, as the biological behaviour of hepatocellular adenoma may be less threatening than presumed. In this study we establish the management of hepatocellular adenoma during pregnancy based on our own experience and literature.

METHODS

Twelve women with documented hepatocellular adenoma were closely monitored during a total of 17 pregnancies between 2000 and 2009. Their files were reviewed.

RESULTS

In four cases, hepatocellular adenomas grew during pregnancy, requiring a Caesarean section in one patient (two pregnancies) at 36 and 34 weeks because of an assumed high risk of rupture. In one case radiofrequency ablation therapy was applied in the first trimester to treat a hormone sensitive hepatocellular adenoma, thereby excluding potential growth later in pregnancy. No intervention was performed in the other 14 cases and all pregnancies had an uneventful course with a successful maternal and fetal outcome.

CONCLUSIONS

A "wait and see" management may be advocated in pregnant women presenting with a hepatocellular adenoma. In women with large tumours or in whom hepatocellular adenoma had complicated previous pregnancies, surgical resection may be recommended. In women with smaller adenomas it may no longer be necessary to discourage pregnancy.

From the archives of the AFIP: Pediatric liver masses: radiologic-pathologic correlation part 1. Benign tumors

Benign hepatic tumors in children include lesions that are unique to the pediatric age group and others that are more common in adults. Infantile hemangioendothelioma, or infantile hepatic hemangioma, is a benign vascular tumor that may cause serious clinical complications. It is composed of vascular channels lined by endothelial cells. At imaging, large feeding arteries and draining veins and early, intense, peripheral nodular enhancement with centripetal filling on delayed images are characteristic features. Mesenchymal hamartoma of the liver occurs in young children and is characterized pathologically by mesenchymal proliferation with fluid-containing cysts of varying size and number. The mesenchymal component or cystic component may predominate; this predominance determines the imaging appearance of the tumor. Benign epithelial tumors that are common in adults may infrequently occur in childhood. These include focal nodular hyperplasia (FNH), hepatocellular adenoma, and nodular regenerative hyperplasia. All are composed of hyperplastic hepatocytes similar to surrounding liver parenchyma and may be difficult to discern at imaging. Preferential hepatic arterial phase enhancement helps distinguish FNH and hepatic adenoma from uninvolved liver. Hepatic adenoma often has intracellular fat and a propensity for intratumoral hemorrhage, neither of which are seen in FNH. Unlike adenoma, FNH often contains enough Kupffer cells to show uptake at sulfur colloid scintigraphy. Nodular regenerative hyperplasia is often associated with portal hypertension, which may be evident at imaging. Knowledge of how the pathologic features of these tumors affect their imaging appearances helps radiologists offer an appropriate differential diagnosis and management plan.

Morphological and functional MDCT: problem-solving tool and surrogate biomarker for hepatic disease clinical care and drug discovery in the era of personalized medicine

This article explains the significant role of morphological and functional multidetector computer tomography (MDCT) in combination with imaging postprocessing algorithms served as a problem-solving tool and noninvasive surrogate biomarker to effectively improve hepatic diseases characterization, detection, tumor staging and prognosis, therapy response assessment, and novel drug discovery programs, partial liver resection and transplantation, and MDCT-guided interventions in the era of personalized medicine. State-of-the-art MDCT depicts and quantifies hepatic disease over conventional CT for not only depicting lesion location, size, and extent but also detecting changes in tumor biologic behavior caused by therapy or tumor progression before morphologic changes. Color-encoded parameter display provides important functional information on blood flow, permeability, leakage space, and blood volume. Together with other relevant biomarkers and genomics, the imaging modality is being developed and validated as a biomarker to early response to novel, targeted anti-VEGF(R)/PDGFR or antivascular/angiogenesis agents as its parameters correlate with immunohistochemical surrogates of tumor angiogenesis and molecular features of malignancies. MDCT holds incremental value to World Health Organization response criteria and Response Evaluation Criteria in Solid Tumors in liver disease management. MDCT volumetric measurement of future remnant liver is the most important factor influencing the outcome of patients who underwent partial liver resection and transplantation. MDCT-guided interventional methods deliver personalized therapies locally in the human body. MDCT will hold more scientific impact when it is fused with other imaging probes to yield comprehensive information regarding changes in liver disease at different levels (anatomic, metabolic, molecular, histologic, and other levels).

Cirrhosis and lesion characterization at MR imaging

Magnetic resonance (MR) imaging has emerged as an important imaging modality for the assessment of cirrhosis and its complications. Faster sequences now allow high-quality liver imaging with high intrinsic soft-tissue contrast. Automated contrast detection methods in combination with faster sequences allow reproducible capture of the arterial phase, which is essential for the detection and characterization of hepatocellular carcinoma. The lack of ionizing radiation permits routine use of gadolinium-enhanced three-dimensional (3D) fat-suppressed multiphasic imaging with high temporal and spatial resolution. In addition, MR imaging allows simultaneous evaluation of the background liver parenchyma and the liver lesions with the combined use of sequences that include T2-weighted sequences, T1-weighted sequences (including chemical shift imaging), echoplanar diffusion-weighted sequences, dynamic gadolinium-enhanced 3D multiphasic imaging, and liver-specific delayed phase sequences (if contrast agents with hepatobiliary excretion are used). The combination of findings from different sequences often helps pinpoint the nature of the liver abnormalities.

A single-center surgical experience of 122 patients with single and multiple hepatocellular adenomas

BACKGROUND & AIMS

Hepatocellular adenoma (HA) is associated with risk of bleeding and malignancy, justifying resection. Patients with multiple forms of HA are difficult to manage. We evaluated the characteristics and outcome of 122 patients with single and multiple HAs after surgery.

METHODS

From 1990 to 2004, 122 patients (14 male) underwent surgical resection. Complications (hemorrhage and malignancy) were assessed according to size, number, and histologic subtype (steatotic, telangiectatic, and unclassified), with a mean follow-up period of 70 months.

RESULTS

Hemorrhagic HA occurred in 21% of cases and malignant HA occurred in 8%. Risk of complications was not related to the number of HAs but was associated with size (>5 cm), especially of telangiectatic and unclassified subtypes. Patients with steatotic HA had a low risk of complications. Malignant HA was more frequent in men (43%); all patients treated by partial resection survived, without recurrent malignancy, after a mean follow-up period of 78 months. After 109 patients with benign HA revealed recurrence or progression of HA in 8% and regression in 9% of cases. No complications were observed in 11 women who became pregnant during the follow-up period.

CONCLUSIONS

Patients with HAs greater than 5 cm, telangiectatic or unclassified subtypes, and men have an increased risk of complicated disease; resection should be restricted to these patients. The risk of complications was not related to the number of HAs, so patients with multiple HAs do not need liver transplantation.

C-11 acetate does not enhance usefulness of F-18 FDG PET/CT in differentiating between focal nodular hyperplasia and hepatic adenoma

PURPOSE OF THE REPORT

We assessed the usefulness of F-18 fluorodeoxyglucose positron emission tomography (FDG PET) and C-11 acetate PET (AC PET) in distinguishing hepatic lesions due to consequential disease (hepatocellular adenoma and malignant lesions) from focal nodular hyperplasia (FNH) in patients at low risk of malignancy.

MATERIALS AND METHODS

Thirty-one patients with 43 lesions were prospectively enrolled. The diagnostic work-up included Doppler and contrast-enhanced ultrasonography, contrast-enhanced computed tomography, and/or magnetic resonance imaging. Fine needle biopsy was performed if the imaging study was inconclusive. The work-up revealed 36 FNH and 7 consequential lesions (5 hepatocellular adenoma, 1 hepatoma, and 1 metastasis). All patients underwent FDG and AC PET. FDG PET with target/background ratio (T/Br) greater than 1.2 and AC PET with T/Br of less than 1.2 were considered positive test for consequential disease.

RESULTS

On FDG PET, we had 6 true-positive out of 7 lesions due to consequential diseases, with a sensitivity of 85.7%, and 33 true-negative out of 36 lesions with FNH, with a specificity of 91.7%. Using AC PET, there were 2 true-positive lesions out of 7 caused by neoplasms, with a sensitivity of 28.6%, and 34 true-negative lesions out of 36 FNH, with a specificity of 94.4%.

CONCLUSIONS

When the goal is differentiating FNH from liver neoplasms, AC PET offered no additional diagnostic advantage over what is achieved with FDG PET.

Hepatocellular adenoma in advanced-stage fatty liver disease

Hepatocellular adenomas are defined as benign hepatocellular neoplasms occurring in otherwise near normal liver and adenomatosis as 10 or more such lesions. We present a case of a 45-year-old man with radiological adenomatosis, histologically confirmed with resection of one lesion, arising within advanced-stage nonalcoholic fatty liver disease (nearly cirrhotic). Hepatocellular adenomas have recently been divided into four categories and the lesion in the present case had morphologic and immunohistochemical features of an inflammatory hepatocellular adenoma. These findings demonstrate that, in contrast to the current dogma, nodules within advanced-stage liver disease may rarely be best classified as adenomas. This should be considered in the radiological differential diagnosis when assessing a patient's suitability for transplantation.

Surgical management of spontaneous ruptured hepatocellular adenoma

AIMS

Spontaneous ruptured hepatocellular adenoma (SRHA) is a rare life-threatening condition that may require surgical treatment to control hemorrhaging and also stabilize the patient. We report a series of emergency surgeries performed at our institution for this condition.

METHODS

We reviewed medical records and radiology files of 28 patients (from 1989 to 2006) with a proven diagnosis of hepatocellular adenoma (HA). Three (10.7%) of 28 patients had spontaneous ruptured hepatocellular adenoma, two of which were associated with intrahepatic hemorrhage while one had intraperitoneal bleeding. Two patients were female and one was male. Both female patients had a background history of oral contraceptive use. Sudden abdominal pain associated with hemodynamic instability occurred in all patients who suffered from spontaneous ruptured hepatocellular adenoma. The mean age was 41.6 years old. The preoperative assessment included liver function tests, ultrasonography and computed tomography.

RESULTS

The surgical approaches were as follows: right hemihepatectomy for controlling intraperitoneal bleeding, and right extended hepatectomy and non-anatomic resection of the liver for intrahepatic hemorrhage. There were no deaths, and the postoperative complications were bile leakage and wound infection (re-operation), as well as intraperitoneal abscess (re-operation) and pleural effusion.

CONCLUSION

Spontaneous ruptured hepatocellular adenoma may be treated by surgery for controlling hemorrhages and stabilizing the patient, and the decision to operate depends upon both the patient's condition and the expertise of the surgical team.

[Diagnosis and differential diagnosis of benign liver tumors and tumor-like lesions]

Benign liver tumors and tumor-like lesions cover a broad spectrum of differential diagnoses, varying from dysontogenetic cysts to pseudolesions. Focal nodular hyperplasia, adenoma and regenerating nodules play a major role in clinical practice. Based on imaging findings, these lesions can be classified as cystic or solid, solitary or multiple, and hyper- or hypovascular. Haemangioma, FNH, steroid-associated adenoma, cystadenoma and echinococcus cysts can be reliably diagnosed using imaging techniques. The same is true for pseudolesions, which are found in particular on dynamic computed tomography. Other entities such as adenoma in cirrhotic livers, angiomyolipoma, regenerating nodules or Echinococcus alveolaris cannot be safely diagnosed by imaging and require biopsy. Morphological and functional characteristics of the most common lesions in the different imaging modalities will be discussed. Where possible, a diagnostic strategy will be presented.