Hepatocellular adenoma: multiphasic CT and histopathologic findings in 25 patients

Hepatocellular Adenomas: Molecular Basis and Multimodality Imaging Update

Hepatocellular adenomas (HCAs) are a family of liver tumors that are associated with variable prognoses. Since the initial description of these tumors, the classification of HCAs has expanded and now includes eight distinct genotypic subtypes based on molecular analysis findings. These genotypic subtypes have unique derangements in their cellular biologic makeup that determine their clinical course and may allow noninvasive identification of certain subtypes. Multiphasic MRI performed with hepatobiliary contrast agents remains the best method to noninvasively detect, characterize, and monitor HCAs. HCAs are generally hypointense during the hepatobiliary phase; the β-catenin-mutated exon 3 subtype and up to a third of inflammatory HCAs are the exception to this characterization. It is important to understand the appearances of HCAs beyond their depictions at MRI, as these tumors are typically identified with other imaging modalities first. The two most feared related complications are bleeding and malignant transformation to hepatocellular carcinoma, although the risk of these complications depends on tumor size, subtype, and clinical factors. Elective surgical resection is recommended for HCAs that are persistently larger than 5 cm, adenomas of any size in men, and all β-catenin-mutated exon 3 HCAs. Thermal ablation and transarterial embolization are potential alternatives to surgical resection. In the acute setting of a ruptured HCA, patients typically undergo transarterial embolization with or without delayed surgical resection. This update on HCAs includes a review of radiologic-pathologic correlations by subtype and imaging modality, related complications, and management recommendations. ^© RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Diagnosis and Follow-up of Incidental Liver Lesions in Children

Incidental liver lesions are identified in children without underlying liver disease or increased risk of hepatic malignancy in childhood. Clinical and imaging evaluation of incidental liver lesions can be complex and may require a multidisciplinary approach. This review aims to summarize the diagnostic process and follow-up of incidental liver lesions based on review of the literature, use of state-of-the-art imaging, and our institutional experience. Age at presentation, gender, alpha fetoprotein levels, tumor size, and imaging characteristics should all be taken into consideration to optimize diagnosis process. Some lesions, such as simple liver cyst, infantile hemangioma, focal nodular hyperplasia (FNH), and focal fatty lesions, have specific imaging characteristics. Recently, contrast-enhanced ultrasound (CEUS) was Food and Drug Administration (FDA)-approved for the evaluation of pediatric liver lesions. CEUS is most specific in lesions smaller than 3 cm and is most useful in the diagnosis of infantile hemangioma, FNH, and focal fatty lesions. The use of hepatobiliary contrast in MRI increases specificity in the diagnosis of FNH. Recently, lesion characteristics in MRI were found to correlate with subtypes of hepatocellular adenomas and associated risk for hemorrhage and malignant transformation. Biopsy should be considered when there are no specific imaging characteristics of a benign lesion. Surveillance with imaging and alpha fetoprotein (AFP) should be performed to confirm the stability of lesions when the diagnosis cannot be determined, and whenever biopsy is not feasible.

Imaging of calcified hepatic lesions: spectrum of diseases

Hepatic calcifications have been increasingly identified over the past decade due to the widespread use of high-resolution Computed Tomography (CT) imaging. Calcifications can be seen in a vast spectrum of common and uncommon diseases, from benign to malignant, including cystic lesions, solid neoplastic masses, and inflammatory focal lesions. The purpose of this paper is to present an updated review of CT imaging findings of a wide range of calcified hepatic focal lesions, which can help radiologists to narrow the differential diagnosis.

Contrast-enhanced ultrasound of benign and malignant liver lesions in children

Contrast-enhanced ultrasound (CEUS) is increasingly being used in children. One of the most common referrals for CEUS performance is characterization of indeterminate focal liver lesions and follow-up of known liver lesions. In this setting, CEUS is performed with intravenous administration of ultrasound contrast agents (UCAs). When injected into a vein, UCA microbubbles remain confined within the vascular network until they dissipate. Therefore, visualization of UCA within the tissues and lesions corresponds to true blood flow. CEUS enables continuous, real-time observation of the enhancement pattern of a focal liver lesion, allowing in most cases for a definite diagnosis and obviating the need for further cross-sectional imaging or other interventional procedures. The recent approval of Lumason (Bracco Diagnostics, Monroe Township, NJ) for pediatric liver CEUS applications has spurred the widespread use of CEUS. In this review article we describe the role of CEUS in pediatric liver applications, focusing on the examination technique and interpretation of main imaging findings of the most commonly encountered benign and malignant focal liver lesions. We also compare the diagnostic performance of CEUS with other imaging modalities for accurate characterization of focal liver lesions.

Steatohepatitic hepatocellular carcinoma: imaging findings with clinicopathological correlation

AIM

To evaluate the clinicopathological and computed tomography (CT) and magnetic resonance imaging (MRI) findings of steatohepatitic hepatocellular carcinoma (SH-HCC).

MATERIALS AND METHODS

Clinicopathological and radiological features were evaluated in 20 patients with SH-HCC. The diagnosis of SH-HCC was made histologically if the tumour had four of the following five characteristics: steatosis (>5% tumour cells), ballooning, Mallory-Denk bodies, interstitial fibrosis, and inflammation. All patients underwent dynamic CT and MRI. CT and MRI images were reviewed for morphological features including tumour size, presence, and distribution of fat, and patterns and degree of contrast enhancement.

RESULTS

Obesity, hypertension, and history of heavy alcohol intake were common clinical findings observed in 10 (50%), 13 (65%), and 11 (55%) of the 20 patients, respectively. Steatosis and steatohepatitis were pronounced in the background liver in 12 (60%) and 10 (50%) patients, respectively. SH-HCC was moderately differentiated in 18 patients (90%) and well differentiated in two (10%). Pathologically, steatohepatitic features were diffuse in 12 (60%) of the 20 tumours and focal in eight (40%). Tumour size and the percentage of intratumoural steatosis were not correlated (r=0.17, p=0.47). On CT, 16 (80%) patients showed arterial phase enhancement and delayed washout. On MRI, 16 (80%) of 20 tumours showed prominent fatty deposition (10 diffusely, six focally) with arterial phase enhancement.

CONCLUSIONS

SH-HCC is likely to show prominent fatty deposits with arterial phase enhancement on CT and MRI. A hypervascular lesion with prominent fatty change should raise the diagnostic suspicion of SH-HCC.

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.

Ultrasound Imaging of Hepatocellular Adenoma Using the New Histology Classification

Hepatocellular adenoma is a rare benign liver tumor. Predisposing factors include hepatic storage diseases and some genetic conditions. A new histology-based classification has been proposed but to date, the corresponding ultrasound imaging features have not been reported. Here we review the new classification scheme and discuss the corresponding features on contrast-enhanced ultrasound imaging.

Exuberant liver adenomatosis presenting with iron deficiency anemia

Intratumoral or intraperitoneal hemorrhage is a recognized complication of liver adenomatosis. We report a case of multifocal massive liver adenomatosis presenting as chronic iron deficiency anemia. Clinicians’ awareness about this atypical presentation not highlighted in the literature is important to allow timely diagnosis and surgical intervention to prevent fatal complications.

Evaluation of the characteristics of hepatic focal nodular hyperplasia: correlation between dynamic contrast-enhanced multislice computed tomography and pathological findings

Objective

To evaluate the characteristics of enhancement of focal nodular hyperplasia (FNH) of the liver by analyzing the dynamic contrast-enhanced multislice computed tomography (MSCT) features and correlating them with pathological findings.

Patients and methods

Nine males and 16 females with pathologically confirmed FNH and complete preoperative contrast-enhanced MSCT data were recruited for this study. The imaging features of FNH on the pre- and postcontrast MSCT were analyzed by two experienced radiologists by consensus.

Results

Pathology showed central scars and abnormal blood vessels in 17 and 21 of 25 lesions, respectively, while MSCT with multiphase enhancement showed central scars in eight of the 17 lesions (47.1%) and abnormal arteries or draining veins in 13 of the 21 lesions (61.9%). Furthermore, abnormal draining veins in five lesions were found to be diagnostic, which is another important finding.

Conclusion

Multiphase scanning can provide the panorama of FNH lesions and reveal their enhancement patterns and pathological characteristics. Abnormal blood vessels within or around the lesion are demonstrated more often than central scar, and both should be observed for FNH diagnosis.

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.

Contemporary management of fibrolamellar hepatocellular carcinoma: diagnosis, treatment, outcome, prognostic factors, and recent developments

Fibrolamellar hepatocellular carcinoma (FL-HCC) is a malignant liver tumor which is thought to be a variant of conventional hepatocellular carcinoma (HCC). It accounts for a small proportion of HCC cases and occurs in a distinctly different group of patients which are young and usually not in the setting of chronic liver disease. The diagnosis of FL-HCC requires the integration of clinical information, imaging studies, and histology. In terms of the treatment options, the only potentially curative treatment option for patients who have resectable disease is surgery either liver resection (LR) or liver transplantation (LT). When performed in a context of aggressive therapy, long-term outcomes after surgery, particularly liver resection for FL-HCC, were favorable. The clinical outcome of patients with unresectable disease is suboptimal with median survival of less than 12 months. The aim of this review is to update the available evidence on diagnosis, treatment options, outcome predictors, and recent developments of patients with this rare disease and to provide a summarized overview of the available literature.

Hepatocyte nuclear factor 1α-inactivated hepatocellular adenomas exhibit high (18)F-fludeoxyglucose uptake associated with glucose-6-phosphate transporter inactivation

OBJECTIVE

This immunohistochemical study aimed to elucidate the molecular mechanism underlying the increased fluorine-18 fludeoxyglucose (FDG) uptake in hepatocyte nuclear factor 1α (HNF1α)-inactivated hepatocellular adenomas (H-HCAs).

METHODS

Three resected H-HCAs were studied using FDG positron emission tomography. Each maximum standardized uptake value (SUVmax) was determined. Resected samples were subjected to immunohistochemical staining for the following glucose metabolism-related proteins: glucose transporter 1 (GLUT1) and glucose transporter 2 (GLUT2), indicative of uptake and transport of glucose into cellular cytoplasm; hexokinase 2 (HK2) and hexokinase 4 (HK4), glucose phosphorylation; glucose-6-phosphate transporter 1 (G6PT1), uptake and transport of glucose-6-phosphate into endoplasmic reticulum; and glucose-6-phosphatase (G6Pase), dephosphorylation.

RESULTS

All three H-HCAs exhibited increased FDG intake, with an average SUVmax of 6.6 (range: 5.2-8.2). No sample expressed GLUT1 and HK2; all the samples exhibited equivalent GLUT2 and HK4 expression, equivalent or slightly increased G6Pase expression and significantly decreased G6PT1 expression relative to the non-neoplastic hepatocytes of background liver.

CONCLUSION

The increased FDG uptake observed in H-HCAs is associated with GLUT2 and HK4 expression and G6PT1 inactivation.

ADVANCES IN KNOWLEDGE

H-HCA exhibits a high FDG uptake owing to the inactivation of G6PT1, which is transcriptionally regulated by HNF1α.

Classification of hypervascular liver lesions based on hepatic artery and portal vein blood supply coefficients calculated from triphasic CT scans

Perfusion CT of the liver typically involves scanning the liver at least 20 times, resulting in a large radiation dose. We developed and validated a simplified model of tumor blood supply that can be applied to standard triphasic scans and evaluated whether this can be used to distinguish benign and malignant liver lesions. Triphasic CTs of 46 malignant and 32 benign liver lesions were analyzed. For each phase, regions of interest were drawn in the arterially enhancing portion of each lesion, as well as the background liver, aorta, and portal vein. Hepatic artery and portal vein blood supply coefficients for each lesion were then calculated by expressing the enhancement curve of the lesion as a linear combination of the enhancement curves of the aorta and portal vein. Hepatocellular carcinoma (HCC) and hypervascular metastases, on average, both had increased hepatic artery coefficients compared to the background liver. Compared to HCC, benign lesions, on average, had either a greater hepatic artery coefficient (hemangioma) or a greater portal vein coefficient (focal nodular hyperplasia or transient hepatic attenuation difference). Hypervascularity with washout is a key diagnostic criterion for HCC, but it had a sensitivity of 72 % and specificity of 81 % for diagnosing malignancy in our diverse set of liver lesions. The sensitivity for malignancy was increased to 89 % by including enhancing lesions that were hypodense on all phases. The specificity for malignancy was increased to 97 % (p = 0.039) by also examining hepatic artery and portal vein blood supply coefficients, while maintaining a sensitivity of 76 %.

Outcomes of liver resection for haemorrhagic hepatocellular adenoma

BACKGROUND

Intratumoral bleeding and/or intraperitoneal rupture occurs in up to 20% of patients with hepatocellular adenoma (HCA). Hepatectomy in the presence of haemorrhagic HCA has been associated with increased morbidity and mortality rates. This study evaluates the outcomes of hepatectomy for haemorrhagic HCA at a single institution.

METHODS

Between January 1997 and December 2012, 52 consecutive patients underwent liver resection for HCA. Among them, 14 patients were resected for haemorrhagic (H)-HCAs (including 9 cases of intratumoural bleeding and 5 cases of intraperitoneal bleeding) and 38 for non-haemorrhagic (NH)-HCAs.

RESULTS

The preoperative characteristics were similar between the two groups except for younger age (p = .001) and shorter duration of hormonal use (p = .001) in (H)-HCAs. There were no mortalities. Intraoperative blood loss, transfusion rate, and postoperative morbidity were comparable between the two groups of patients (p = ns). The length of hospital stay was significantly longer in (H)-HCAs (p = .03). In all the resected H-HCAs, pathology showed central haemorrhagic changes with tumoral cells at the periphery of the lesions.

CONCLUSIONS

Liver resection for H- and NH-HCAs can be achieved with no mortality and comparable short-term outcomes.

Management of hepatic adenomatosis

Hepatic adenomatosis (HeAs) is a rare clinical entity defined by the presence of 10 or more hepatic adenomas (HA) within the background of an otherwise normal liver parenchyma, in the absence of glycogen storage disease or anabolic steroid use. HA is a benign tumor associated with oral contraceptive use. Recent advances in pathogenesis and classification of HA have questioned the distinction between these two diseases. HA are currently classified into four different subtypes with genotypic and phenotypic correlation: HNF-1a inactivated HA, B-catenin activated HA, inflammatory HA, and undetermined subtype. The clinical presentation of HA depends on the lesion size and the subtype. MRI using hepatospecific contrast agents is helpful in diagnosing the most common subtypes. When diagnosis is uncertain, biopsy with immunohistochemistry is used to diagnose and classify the lesions. Management is governed by the molecular subtype and tumor size. Pregnancy is not routinely discouraged but management is individualized.

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.

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.

Benign liver lesions: grey-scale and contrast-enhanced ultrasound appearances

Ultrasound is often the first point of detection of liver lesions, with up to 75% of liver lesions detected at ultrasound having benign histology. In 2012, NICE issued recommendations that ultrasound contrast be used for the evaluation of incidentally discovered liver lesions. This has been demonstrated to provide a rapid and cost-effective evaluation for incidental liver lesions, in many cases precluding the need for further CT or MRI scans. The aim of this review is to demonstrate the ultrasound features of benign liver lesions, and to demonstrate their further characterisation with contrast ultrasound.

Quantitative evaluation of enhancement patterns in focal solid liver lesions with Gd-EOB-DTPA-enhanced MRI

Purpose

The objective was to investigate the dynamic enhancement patterns in focal solid liver lesions after the administration of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) by means of dynamic magnetic resonance imaging (MRI) including hepatobiliary phase (HP) images 20 min after Gd-EOB-DTPA administration.

Materials and Methods

Non-enhanced T1/T2-weighted as well as dynamic magnetic resonance (MR) images during the arterial phase (AP), the portal venous phase (PVP), the late phase (LP), and the HP (20 min) were obtained from 83 patients (54 male, 29 female, mean age 62.01 years) with focal solid liver lesions. MRI was conducted by means of a 1.5-T system for 63 patients with malignant liver lesions (HCCs: n = 34, metastases: n = 29) and for 20 patients with benign liver lesions (FNH lesions: n = 14, hemangiomas: n = 3, adenomas: n = 3). For quantitative analysis, signal-to-noise ratios (SNR), contrast enhancement ratios (CER), lesion-to-liver contrast ratios (LLC), and signal intensity (SI) ratios were measured.

Results

The SNR of liver parenchyma significantly increased in each dynamic phase after Gd-EOB-DTPA administration compared to the SNR of non-enhanced images (p<0.001). The CER of HCCs and metastases significantly decreased between LP and HP images (p = 0.0011, p<0.0001). However, FNH lesions did not show any significant difference, whereas an increased CER was found in hemangiomas. The mean LLCs of FNH lesions were significantly higher than those of HCCs and metastases. The LLC values of hemangiomas remained negative during the entire time course, whereas the LLC of adenomas indicated hyperintensity from the AP to the LP. Furthermore, adenomas showed hypointensity in HP images.

Conclusion

Gd-EOB-DTPA-enhanced MRI may help diagnose focal solid liver lesions by evaluating their enhancement patterns.

Hepatic adenomatosis: spectrum of imaging findings

OBJECTIVE

This pictorial essay reviews the imaging appearance and differential diagnosis of hepatic adenomatosis.

CONCLUSION

In addition to such entities as multifocal hepatocellular carcinoma, metastases, and multiple focal nodular hyperplasia, hepatic adenomatosis should also be considered when confronted with multiple hypervascular liver lesions. Certain CT and MRI features can strongly suggest the diagnosis of adenomatosis.

Hepatic arterial phase and portal venous phase computed tomography for dose calculation of stereotactic body radiation therapy plans in liver cancer: a dosimetric comparison study

Purpose

To investigate the effect of computed tomography (CT) using hepatic arterial phase (HAP) and portal venous phase (PVP) contrast on dose calculation of stereotactic body radiation therapy (SBRT) for liver cancer.

Methods

Twenty-one patients with liver cancer were studied. HAP, PVP and non-enhanced CTs were performed on subjects scanned in identical positions under active breathing control (ABC). SBRT plans were generated using seven-field three-dimensional conformal radiotherapy (7 F-3D-CRT), seven-field intensity-modulated radiotherapy (7 F-IMRT) and single-arc volumetric modulated arc therapy (VMAT) based on the PVP CT. Plans were copied to the HAP and non-enhanced CTs. Radiation doses calculated from the three phases of CTs were compared with respect to the planning target volume (PTV) and the organs at risk (OAR) using the Friedman test and the Wilcoxon signed ranks test.

Results

SBRT plans calculated from either PVP or HAP CT, including 3D-CRT, IMRT and VMAT plans, demonstrated significantly lower (p <0.05) minimum absorbed doses covering 98%, 95%, 50% and 2% of PTV (D98%, D95%, D50% and D2%) than those calculated from non-enhanced CT. The mean differences between PVP or HAP CT and non-enhanced CT were less than 2% and 1% respectively. All mean dose differences between the three phases of CTs for OARs were less than 2%.

Conclusions

Our data indicate that though the differences in dose calculation between contrast phases are not clinically relevant, dose underestimation (IE, delivery of higher-than-intended doses) resulting from CT using PVP contrast is larger than that resulting from CT using HAP contrast when compared against doses based upon non-contrast CT in SBRT treatment of liver cancer using VMAT, IMRT or 3D-CRT.

[Steatohepatitis--a challenge?]

CLINICAL/METHODICAL ISSUE

With the increasing use of cross-sectional imaging techniques both diffuse and focal fat accumulations in the liver are frequent incidental findings. Focal fatty changes in particular, such as localized distribution disorders in steatohepatitis or focal fat deposition of the liver, can lead to difficulties in the correct diagnosis of patients with a history of malignant disease.

STANDARD RADIOLOGICAL METHODS

Ultrasound is used as the first imaging modality in most cases but has a relatively low sensitivity and specificity. In most cases a further diagnosis of diffuse fatty liver accumulations is possible with non-contrast computed tomography (CT) scanning and chemical shift imaging in magnetic resonance imaging (MRI) enabling an even further differential diagnostic distinction of fatty disorders of the liver.

PERFORMANCE

For the detection of generalized fatty liver disease ultrasound has a sensitivity and specificity of 60-100% and 77-95%, respectively. Non-contrast CT of the liver attains a sensitivity of between 43% and 95% with a specificity of 90%. Sensitivity and specificity for chemical shift imaging of MRI are 81% and 100%, respectively.

PRACTICAL RECOMMENDATIONS

For advanced differential diagnostic distinction of the different forms of fatty liver disorders and for the correct diagnosis of benign and malignant liver lesions the leading imaging modality is chemical shift imaging of MRI (in-phase and opposed-phase).

Pathological Diagnosis of Hepatocellular Cellular Adenoma according to the Clinical Context

In Europe and North America, hepatocellular adenomas (HCA) occur, classically, in middle-aged woman taking oral contraceptives. Twenty percent of women, however, are not exposed to oral contraceptives; HCA can more rarely occur in men, children, and women over 65 years. HCA have been observed in many pathological conditions such as glycogenosis, familial adenomatous polyposis, MODY3, after male hormone administration, and in vascular diseases. Obesity is frequent particularly in inflammatory HCA. The background liver is often normal, but steatosis is a frequent finding particularly in inflammatory HCA. The diagnosis of HCA is more difficult when the background liver is fibrotic, notably in vascular diseases. HCA can be solitary, or multiple or in great number (adenomatosis). When nodules are multiple, they are usually of the same subtype. HNF1 α -inactivated HCA occur almost exclusively in woman. The most important point of the classification is the identification of β -catenin mutated HCA, a strong argument to identify patients at risk of malignant transformation. Some HCA already present criteria indicating malignant transformation. When the whole nodule is a hepatocellular carcinoma, it is extremely difficult to prove that it is the consequence of a former HCA. It is occasionally difficult to identify HCA remodeled by necrosis or hemorrhage.

Molecular pathogenesis of hepatic adenomas and its implications for surgical management

INTRODUCTION

Hepatic adenomas (HAs) are benign tumors of the liver, which can be solitary or multiple, and have a definite risk of malignant degeneration.

DISCUSSION

The pathogenesis and natural history of this disease entity were previously unknown. Recent research into the molecular pathogenesis of this condition has provided evidence for the malignant transformation of some of these adenomas. In the current article, we discuss the current evidence on the molecular biology underlying malignant transformation of hepatic adenomas and the implications for the surgical management of this disease.

A new long term hepatic complication in survivors of childhood haematological malignancy

Hepatic abnormalities have been documented in survivors of childhood malignancies and a spectrum of liver diseases has been described in this group The risk factors for liver disease include: hepatic surgery; radiotherapy to field including liver; total body irradiation (TBI); chemotherapy, multiple blood transfusions and use of hematopoietic cell transplantation. We report three cases of hepatic adenomatosis (HA) in young women who had been treated for haematological malignancy as children and had bone marrow transplant. These women were on estrogen and growth hormone replacement. They had mild abnormalities of liver function tests. The diagnosis of HA was made on liver imaging and confirmed by liver biopsy. We also propose a hypothesis for the pathogenesis of hepatic adenomatosis in these patients which vascular damage, estrogen replacement and growth hormone deficiency.

CT scan diagnosis of hepatic adenoma in a case of von Gierke disease

Hepatic adenoma is a well-defined, benign, solitary tumor of the liver. In individuals with glycogen storage disease I, adenoma tends to occur at a relatively younger age and can be multiple (adenomatosis). Imaging plays a pivotal role in diagnosing hepatic adenoma and in differentiating adenoma from other focal hepatic lesions. Especially in patients with von Gierke disease, in addition to the associated hepatomegaly caused by steatohepatitis and the diffusely reduced attenuation of the liver parenchyma seen on CT, there may be more than one hepatic adenoma in up to 40% of patients. Malignant degeneration of hepatic adenoma into hepatocellular carcinoma can occur and hence imaging is important for prompt diagnosis of adenoma and its complications. In this case report, we present a case of liver adenoma diagnosed by CT scan in a patient with von Gierke disease.

Beta-catenin-activated hepatocellular adenoma showing hyperintensity on hepatobiliary-phase gadoxetic-enhanced magnetic resonance imaging and overexpression of OATP8

We report a male case of beta-catenin-activated hepatocellular adenoma (HCA) focusing on findings of gadoxetic-acid-enhanced magnetic resonance imaging (EOB-MRI) and discussing the molecular background and possible clinical significance. The patient was a 31-year-old man in whom computed tomography (CT) showed a large nodule of 14 cm in diameter in the right liver lobe. On dynamic contrast-enhanced CT, heterogeneous and slight to moderate enhancement was observed during the early phase, with washout in the late phase. Focal fat deposits and a scar-like portion in the lesion were also seen. Most of the lesion was slightly hyperintense compared with the background liver on the hepatobiliary phase of EOB-MRI. After operation, this patient was confirmed pathologically as having beta-catenin-activated HCA with a portion suggestive of malignant transformation. In addition, intense organic anion transporter polypeptide 8 expression was observed throughout the tumor by immunohistochemical staining.

Focal hepatic lesions in Gd-EOB-DTPA enhanced MRI: the atlas

Objective

This article reviews the different technical aspects and pitfalls of gadolinium (Gd)-ethoxibenzyl (EOB)-diethylenetriamine pentaacetic acid (DTPA) and the advantages of the hepatocellular phase (HCP) and defines its specific imaging features of liver lesions.

Background

Gd-EOB-DTPA is a contrast agent with combined properties of a conventional non-specific extracellular and a hepatocyte-specific contrast agent. Benign cirrhosis-associated nodules are characterised by isointensity in dynamic imaging and the HCP. Hepatocellular carcinomas (HCCs) usually show hyperenhancement in the arterial phase, with washout in the portal vein pressure (PVP) and hypointensity in the HCP. Among other characteristic findings, we have the mosaic pattern, a capsule, the “nodule-in-nodule” appearance and the satellite nodules. The fibrolamellar HCC is a large enhancing heterogeneous lesion, on a non-cirrhotic liver, with a hypointense scar in every sequence. THIDs (transient hepatic intensity differences) are perfusional alterations, characterised by hyperintensity in the arterial phase, with no alterations in the rest of the sequences including the HCP. Adenoma and focal nodular hyperplasia (FNH) are lesions, occurring more frequently in young women, with brisk arterial enhancement, differentiated by the scar and the uptake of Gd-EOB-DTPA in the HCP. Focal eosinophilic infiltration is a difficult diagnosis, with characteristics such as a non-spherical shape and irregular borders suggesting it. Besides these lesions, in which Gd-EOB-DTPA has a clear advantage, there are a few where the specificities of this agent can be troublesome: haemangiomas, focal fat/sparing, foreign body reaction, cholangiocarcinoma and metastases.

Conclusion

Gd-EOB-DTPA is comparable to extracellular agents, and uptake by functioning hepatocytes in the delayed phase provides additional information that further improves detection and characterisation of many hepatic lesions.

Main Messages

Gd-EOB-DTPA offers advantages for the imaging of many liver lesions including HCC, fibrolamellar HCC, FNH and adenoma.

The properties of Gd-EOB-DTPA can pose problems when dealing with haemangiomas, cholangiocarcinoma and metastases among others.

The uptake of Gd-EOB-DTPA by functioning hepatocytes in the delayed phase provides additional information that further improves detection and characterisation of many hepatic lesions.

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.

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.

Genetics and imaging of hepatocellular adenomas: 2011 update

Hepatocellular adenomas are benign liver neoplasms with specific but varied histopathologic findings and tumor biology. The results from recent studies of the pathologic and genetic basis of hepatocellular adenomas provide important insights into the pathogenesis and molecular changes, as well as the putative oncologic pathways used by diverse adenoma subtypes. On the basis of the genetic and pathologic features, hepatocellular adenomas are categorized into three distinct subtypes: (a) inflammatory hepatocellular adenomas, (b) hepatocyte nuclear factor 1 α-mutated hepatocellular adenomas, and (c) β-catenin-mutated hepatocellular adenomas. Different subtypes show variable clinical behavior, imaging findings, and natural history, and thus the options for treatment and surveillance may vary. Cross-sectional imaging plays an important role in the diagnosis, subtype characterization, identification of complications, and surveillance of hepatocellular adenomas. New schemas for genotype-phenotype classification of hepatic adenomas, as well as management triage of patients with specific subtypes of adenomas, are being proposed in an attempt to improve clinical outcomes.

Liver-specific contrast agent-enhanced magnetic resonance and ¹⁸F-fluorodeoxyglucose positron emission tomography findings of hepatocellular adenoma: report of a case

We report a case of hepatocellular adenoma, focusing on the findings of liver-specific contrast agent-enhanced magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET). The patient was a 37-year-old woman, referred to us after contrast-enhanced computed tomography showed a homogeneous, poorly enhanced liver tumor, 2.8 cm in diameter. Magnetic resonance imaging showed a liver mass with significant fatty change. The tumor increased in size to 3.3 cm over 9 months of follow-up. Gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid-enhanced MRI revealed spotty enhancement in the hypointense tumor in the hepatobiliary phase. Subsequent FDG-PET showed increased uptake of FDG (maximum standardized uptake value 5.0), which suggested the possibility of malignancy. The patient underwent partial hepatectomy, and histological examination of the resected specimen revealed a tumor composed of hepatocyte-like cells with minimal cellular atypia and significant diffuse fatty change. Based on these findings, we diagnosed hepatocellular adenoma.

Contrast-enhanced ultrasound for the diagnosis of hepatic adenoma

Nine hepatic adenomas (HA) diagnosed by contrast-enhanced ultrasound (CEUS) among 123 liver lesions (89 patients) were evaluated retrospectively; five were confirmed through pathological diagnosis. Time-intensity curves (TIC), contrast medium arriving time (AT), peak time (PT) and retrogression time (RT) for HA were compared with 30 hepatocellular carcinomas (HCC) and six focal nodular hyperplasias (FNH). Significant differences existed between HA and poorly-differentiated HCC in AT, PT and RT, and between HA and well-differentiated HCC in AT. Differential diagnosis between HA and FNH was determined only through their different perfusion and arterial morphological features: HA showed typical perfusion characteristic of 'fast-in, slow-out', with a centripetal or mixed-filling pattern in the arterial phase, while FNH showed a centrifugal filling pattern. In conclusion, CEUS was helpful for identifying HA but it may be relatively difficult to distinguish between HA and some well-differentiated HCC or FNH.

Hepatocellular carcinoma arising from hepatocellular adenoma in a hepatitis B virus-associated cirrhotic liver

Hepatocellular adenoma (HCA) is a rare, benign proliferation of hepatocytes that occurs mostly in a normal liver and in extreme rare cases, occurs in a cirrhotic liver. Hepatocellular carcinomas (HCC) arising within HCA through malignant transformation is rare. The specific incidence and mechanism of malignant transformation has not been established, but the long term use of oral contraceptives is considered a causative agent. We report a case of HCC arising from HCA detected in a hepatitis B-related cirrhotic liver with serial radiologic images.

The role of hepatocyte-specific staining in liver pathology

The advantages of MRI in the investigation of liver disease are well documented. Recent developments, including fast scanning technique and new MRI contrast agents, enable improved detection and characterization of focal liver lesions. Therefore, a definitive diagnosis can be made avoiding invasive procedures, such as liver biopsy. In this article, a special emphasis is placed on the clinical use of combined perfusional and hepatocyte-selective MRI contrast agents, which allow us to obtain morphologic and vascular information, owing to the dynamic study, as well as functional information, owing to the hepatocyte-selective phase of enhancement. Different clinical scenarios are considered in order to highlight the proper use of the hepatocyte phase to noninvasively characterize and detect different focal liver lesions.

Hepatocellular adenomas: current update on genetics, taxonomy, and management

Hepatocellular adenomas (HCAs) are uncommon, benign hepatocellular neoplasms that commonly occur in young women. Recent advances in pathology and cytogenetics have thrown fresh light on the pathogenesis of HCAs leading to classification of HCAs into 3 distinct subtypes, each with a characteristic epidemiology, histopathology, oncogenesis, and imaging findings. The aim of the article was to provide a comprehensive review of contemporary taxonomy of HCAs, with an emphasis on cross-sectional imaging findings and management.

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.

Malignant transformation of hepatocellular adenomas into hepatocellular carcinomas: a systematic review including more than 1600 adenoma cases

BACKGROUND

Malignant transformation of hepatocellular adenomas (HCAs) into hepatocellular carcinomas (HCCs) has been reported repeatedly and is considered to be one of the main reasons for surgical treatment. However, its actual risk is currently unknown.

OBJECTIVE

To provide an estimation of the frequency of malignant transformation of HCAs and to discuss its clinical implications.

METHODS

A systematic literature search was conducted using the following databases: The Cochrane Hepatobiliary Group Controlled Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, MEDLINE and EMBASE.

RESULTS

One hundred and fifty-seven relevant series and 17 case reports (a total of 1635 HCAs) were retrieved, reporting an overall frequency of malignant transformation of 4.2%. Only three cases (4.4%) of malignant alteration were reported in a tumour smaller than 5 cm in diameter.

DISCUSSION

Malignant transformation of HCAs into HCCs remains a rare phenomenon with a reported frequency of 4.2%. A better selection of exactly those patients presenting with an HCA with an amplified risk of malignant degeneration is advocated in order to reduce the number of liver resections and thus reducing the operative risk for these predominantly young patients. The Bordeaux adenoma tumour markers are a promising method of identifying these high-risk adenomas.

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.

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.

Liver nodules after portal systemic shunt surgery for extrahepatic portal vein obstruction in children

BACKGROUND

Liver nodules have been reported after portal systemic shunt surgery (PSSS) in animal experiments or in humans with liver cirrhosis. The aim of our study was to assess the incidence of liver nodules after surgery for extrahepatic portal vein obstruction (EHPVO) in children without associated liver disease.

METHODS

We retrospectively reviewed the charts of 45 children who had surgery from 1979 to 2005 for EHPVO in our institution, consisting of 38 PSSS and 7 portal reperfusion procedures (PRPs). We assessed the presence of liver nodules on ultrasonography.

RESULTS

Of 45 patients, 7 (15%) had liver nodules during a median of 80 months of follow-up. All the nodules occurred after PSSS. Five nodules were subjected to biopsy; we found 2 liver cell adenomas and 3 focal nodular hyperplasias.

CONCLUSIONS

In this study, liver nodules occurred in 18% of cases after PSSS for EHPVO in children and not after PRP. As many children have undergone PSSS throughout the world, the presence of liver nodules should be considered during the follow-up of those patients.

Approach to a liver mass

Incidentally discovered liver masses are becoming more common with the increasing application and power of imaging techniques for the evaluation of abdominal conditions. Although such masses are often benign, conclusive diagnoses must be established in order to provide appropriate patient care. Various imaging modalities can be utilized to accurately diagnose such masses without resort to more invasive diagnostic measures.