Liver adenomatosis: clinical, histopathologic, and imaging findings in 15 patients

Hepatic Precancerous Lesions and Early Hepatocellular Carcinoma

This review discusses the diagnostic challenges of diagnosing and treating precursor lesions of hepatocellular carcinoma (HCC) in both cirrhotic and non-cirrhotic livers. The distinction of high-grade dysplastic nodule (the primary precursor lesion in cirrhotic liver) from early HCC is emphasized based on morphologic, immunohistochemical, and genomic features. The risk factors associated with HCC in hepatocellular adenomas (precursor lesion in non-cirrhotic liver) are delineated, and the risk in different subtypes is discussed with emphasis on terminology, diagnosis, and genomic features.

Fatal rupture of hepatic adenomatosis: Autopsy case and review of the literature

Hepatic adenomatosis is a rare disease consisting of multiple adenomas in otherwise-normal liver parenchyma. Though the discovery of this entity goes back several years, its diagnosis is still challenging in terms of its definition and pathophysiology. Clinically, patients may be completely asymptomatic and the diagnosis is only made incidentally through imaging tests. The discovery could be made when complications occur such as intraperitoneal hemorrhage with hypovolemic shock due to the rupture of an adenoma. We report a fatal case of a ruptured adenoma in a case of hepatic adenomatosis discovered at autopsy. In order to achieve a better view of this disease, we conducted a literature review on this subject describing the pathogenesis, manifestations, and autopsy contribution to addressing this entity.

Benign liver lesions 2022: Guideline for clinical practice of Associazione Italiana Studio del Fegato (AISF), Società Italiana di Radiologia Medica e Interventistica (SIRM), Società Italiana di Chirurgia (SIC), Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB), Associazione Italiana di Chirurgia Epatobilio-Pancreatica (AICEP), Società Italiana Trapianti d'Organo (SITO), Società Italiana di Anatomia Patologica e Citologia Diagnostica (SIAPEC-IAP) - Part II - Solid lesions

Benign liver lesions are increasingly diagnosed in daily clinical practice due to the growing use of imaging techniques for the study of the abdomen in patients who have non-specific symptoms and do not have an increased risk of hepatic malignancy. They include simple or parasitic hepatic cysts and solid benign tumors which differ widely in terms of prevalence, clinical relevance, symptoms and natural history and often lead to significant clinical problems relating to diagnosis and clinical management. Following the need to have updated guidelines on the management of benign focal liver lesions, the Scientific Societies mainly involved in their management have promoted the drafting of a new dedicated document. This document was drawn up according to the present Italian rules and methodologies necessary to produce clinical, diagnostic, and therapeutic guidelines based on evidence. Here we present the second part of the guideline, concerning the diagnosis and clinical management of hemangioma, focal nodular hyperplasia, and hepatocellular adenoma.

Contrast-Enhanced Ultrasound as a Problem-Solving Modality: Tips and Tricks

ABSTRACT

Contrast-enhanced ultrasound (CEUS) continues to be an ever-growing tool in radiation-free imaging. While it has been widely used in cardiac imaging, CEUS has only recently become an Food and Drug Administration-approved and viable modality for evaluation of abdominal structures. Ultrasound contrast agents are nontoxic, microbubble-based vascular agents and can be used to reliably assess enhancement patterns of various lesions in real time. In particular, it's non nephrotoxic nature makes CEUS a particularly important tool in renal failure patients requiring serial follow-up. This review provides a comprehensive discussion on the utility of CEUS agents, imaging techniques, comparison with traditional cross-sectional imaging modalities, and its application in diagnosing kidney and liver lesions. This pictorial review is illustrated with cases of renal and hepatic lesions that the practicing radiologist should become familiar with as CEUS becomes increasingly popular.

A Scoping Review of the Classification, Diagnosis, and Management of Hepatic Adenomas

BACKGROUND

Hepatic adenomas (HA), or hepatocellular adenomas, are benign, solid liver lesions that develop in otherwise normal livers, often in the setting of increased estrogen levels. While considered a benign tumor, there is a risk for substantial complications such as hemorrhage and malignant transformation. We review the diagnosis, classification, and potential therapeutic management options for patients with HA.

METHODS

A scoping narrative review was conducted based on recent literature regarding classification, diagnosis, and management of HA.

RESULTS

While HAs are typically considered benign, complications such as hemorrhage and malignant transformation may occur in approximately 25% and 5% of patients, respectively. Recent advances in imaging and molecular profiling have allowed for the classification of HAs into subtypes allowing for patient risk stratification that helps guide management. Surgical resection should be considered in asymptomatic patients who are male, have an adenoma ≥5 cm in diameter, or have the β-catenin-activated subtype due to an increased risk of hemorrhage and/or malignant transformation.

CONCLUSION

Molecular profiling has aided in the stratification of patients relative to the risk of complications to predict better the potential behavior of HAs.

Diagnosis of Hepatocellular Carcinoma Using Gd-EOB-DTPA MR Imaging

Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA; Gadoxetic acid; Gadoxetate disodium) is a hepatocyte-specific MR contrast agent. It acts as an extracellular contrast agent in the early phase after intravenous injection, and then is taken up by hepatocytes later. Using this contrast agent, we can evaluate the hemodynamics of the liver and liver tumors, and can therefore improve the detection and characterization of hepatocellular carcinoma (HCC). Gd-EOB-DTPA helps in the more accurate detection of hypervascular HCC than by other agents. In addition, Gd-EOB-DTPA can detect hypovascular HCC, which is an early stage of the multi-stage carcinogenesis, with a low signal in the hepatobiliary phase. In addition to tumor detection and characterization, Gd-EOB-DTPA contrast-enhanced MR imaging can be applied for liver function evaluation and prognoses evaluation. Thus, Gd-EOB-DTPA plays an important role in the diagnosis of HCC. However, we have to employ optimal imaging techniques to improve the diagnostic ability. In this review, we aimed to discuss the characteristics of the contrast media, optimal imaging techniques, diagnosis, and applications.

Case Report: Hepatic Adenoma in a Child With a Congenital Extrahepatic Portosystemic Shunt

Congenital extrahepatic portosystemic shunts (CEPS), previously also described as Abernethy malformations, are rare malformations in which the extrahepatic portal system directly communicates with the vena cava inferior, thereby bypassing the liver. A hypoplastic portal vein (PV) exists in most cases. CEPS have been associated with the development of liver nodules, ranging from mostly focal nodular hyperplasia (FNH) to hepatic adenoma (HA) and even hepatocellular carcinoma (HCC). Tumor development in CEPS may be due to changes in perfusion pressures, oxygen supply or endocrine imbalances. It is important to rule out CEPS in children with liver tumors, because resection could impede future shunt occlusion procedures, and benign masses may regress after shunt occlusion. Here, we review the case of a 9-years-old male with CEPS and hepatic nuclear Factor 1-alpha (HNF-1-alpha) inactivated HA to raise awareness of this condition and review histopathological changes in the liver of CEPS.

Liver adenomatosis in patients with hepatocyte nuclear factor-1 alpha maturity onset diabetes of the young (HNF1A-MODY): Clinical, radiological and pathological characteristics in a French series

BACKGROUND

Liver adenomatosis (LA) is a rare disease resulting from biallelic inactivation of the hepatocyte nuclear factor-1 alpha (HNF1A) gene, which induces the proliferation of adenoma cells in liver parenchyma. Liver adenomatosis has only been documented in case reports from patients carrying a HNF1A germline mutation. We have evaluated the frequency of LA among a large cohort of patients with HNF1A-maturity onset diabetes of the young (MODY), previously termed "MODY3," and herein describe its clinical, radiological, and pathological characteristics.

METHODS

In all, 137 HNF1A-MODY subjects from 74 families were screened by liver ultrasonography in 13 centers, and 15 additional cases of LA were later included in the series. Liver adenomatosis was confirmed by liver computed tomography, magnetic resonance imaging (MRI), and/or histopathology.

RESULTS

Among 137 carriers of an HNF1A mutation, 9 patients (6.5%) from seven families were diagnosed with LA. Diabetes mellitus was present in 87.5% of patients with LA. In 25% of patients, LA was diagnosed due to intra-abdominal or intratumoral bleeding. Liver biochemistry was near normal in all patients. Liver imaging showed adenomas of various sizes and numbers. On MRI, most nodules had the radiological characteristics of steatotic adenomas. Histopathological confirmation of LA was available in 13 cases, and these adenomas were mostly steatotic. Surgery was initially performed in 37.5% of patients, and liver disease progression was observed in 30%. No disease progression was observed in 14 pregnancies.

CONCLUSIONS

The frequency of LA in a cohort of screened HNF1A-MODY patients and the high incidence of LA progression and/or hemorrhage warrants systematic screening for liver adenomatosis in HNF1A-MODY families.

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.

Current Approaches in the Management of Hepatic Adenomas

INTRODUCTION

Hepatic adenomas (HAs) are a benign and relatively rare type of liver neoplasms. We review the diagnosis, evaluation, and potential therapeutic management options for patients with HA.

METHODS

A comprehensive review of the English literature was performed utilizing MEDLINE/PubMed and Web of Science databases with end of search date the 30th April of 2018. In PubMed, the terms "hepatocellular," "hepatic," "liver," and "adenoma," "adenomatosis" were searched in the title and/or abstract.

RESULTS

Recent advances in molecular classification of HA have determined distinct subtypes with specific clinical, pathological, and imaging characteristics. In general, cessation of exogenous hormonal administration or weight loss may lead to HA regression. Surgical resection, either open or laparoscopic, should be considered in patients with symptoms and risk factors for hemorrhage or malignant transformation. These risk factors include tumor diameter greater than 5 cm, β-catenin activated subtype, and/or male gender. The management of acute hemorrhage should primarily aim at achieving hemodynamic stability via angioembolization followed by elective resection, whereas malignant transformation is treated according to oncologic resection principles. Although pregnancy is one of the known risk factors for tumor growth and associated complications, the presence of an HA per se should not be considered a contradiction to pregnancy.

CONCLUSION

Future genomic-based multicenter studies are required to provide a strong basis for formulating an evidence-based risk-adapted model that guides individualized management strategies for patients with HA.

Long-term follow-up of hepatic adenoma and adenomatosis: analysis of size change on imaging with histopathological correlation

AIM

To analyse the change in size on follow-up of hepatic adenomas (HAs) and adenomatosis, and to investigate the relationship of imaging features with size change.

MATERIALS AND METHODS

The study included 44 patients (142 lesions) who underwent magnetic resonance imaging (MRI) or computed tomography (CT) for diagnosis and follow-up of HA. The imaging features and percentage change in maximum tumour dimension were observed over a follow-up duration of up to 139 months.

RESULTS

With an average follow-up of 43 months, 37% lesions decreased in size, 58% were stable, 4% increased; one lesion regressed completely. Adenomas were stratified into size groups (<3, 3-5, and ≥5 cm). Size change among the three groups was similar (p>0.05). Percent size change was different for lesions followed for ≤12 months (-7.2%) compared with lesions followed for 13-60 months (-20.5%), and those followed for ≥60 months (-23.5%; p<0.05); there was no difference between lesions followed for 13-60 months and ≥60 months (p=0.523). Baseline size and percent size change was similar between the hepatocyte nuclear factor 1α-inactivated HA (HA-H) and inflammatory HA (HA-I) subtype (p>0.05).

CONCLUSION

Most adenomas were either stable or regressed on follow-up. Size change was independent of baseline size. After an initial size decrease within 5 years, no further size reduction was noted on extended follow-up. The percent size change in the HA-H and HA-I subtype was similar.

A First Report of Synchronous Intracapsular and Extracapsular Hepatic Adenoma

Although the gallbladder is the most common site of ectopic liver, it has been reported in many other organs, such as kidney, adrenal glands, pancreas, omentum, stomach, esophagus, mediastinum, lungs, and heart. Hepatocytes in an ectopic liver behave like normal hepatocytes; furthermore, they can be associated with the same pathological findings as those in the main liver. Ectopic liver in the gallbladder can undergo fatty change, hemosiderosis, cholestasis, cirrhosis, hemangioma, focal nodular hyperplasia, adenoma, and even carcinogenesis. The incidence of extracapsular hepatic adenoma is not known, but only two cases have been reported. Here, we provide the first case report of synchronous multiple intracapsular and extracapsular hepatic adenomas. A 60-year-old woman with multiple hepatic adenomas and one 7 × 5 × 5 cm ectopic hepatic adenoma attached to the gallbladder fundus complicated with abdominal pain is presented.

Inflammatory hepatic adenomas: Characterization with hepatobiliary MRI contrast agents

PURPOSE

To characterize the MRI appearance of inflammatory hepatic adenomas using hepatobiliary contrast agents.

MATERIALS AND METHODS

MRI was performed using hepatobiliary contrast agents (3 with gadobenate dimeglumine and 24 with gadoxetic acid) in 27 patients with immunohistochemistry-confirmed diagnosis of inflammatory hepatic adenoma. The appearance of the lesions on T2 and diffusion-weighted images, pre-gadolinium T1-weighted images, dynamic post-gadolinium images, and hepatobiliary phase images was assessed.

RESULTS

Seven lesions (26%) showed predominant hyperenhancement on hepatobiliary phase images in comparison with adjacent hepatic parenchyma: 1 lesion showed diffuse, mildly heterogeneous hyperenhancement, and the remaining 6 lesions showed peripheral hyperenhancement and central hypoenhancement. Twenty lesions (74%) were predominantly hypoenhancing compared to adjacent liver on hepatobiliary phase images. Nine lesions showed a pattern of peripheral hyperenhancement and central hypoenhancement on hepatobiliary phase images; in 6 of these lesions a majority of the mass appeared hyperenhancing, while the remaining 3 lesions showed predominant hypoenhancement.

CONCLUSIONS

This investigation shows that a significant percentage of inflammatory hepatic adenomas appear isointense or hyperintense in comparison to adjacent normal liver on hepatobiliary phase images, and therefore this feature should not be used to distinguish hepatic adenomas from focal nodular hyperplasia without additional supporting evidence.

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.

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.

[Extracapsular hepatic adenoma. Case report and literature review]

BACKGROUND

Hepatic adenomas are uncommon epithelial tumours. They usually appear in women between 20 and 44 years old. They are commonly located in the right hepatic lobe and are typically solitary masses. Multiple adenomas can present in patients with prolonged use of oral contraceptive pills, glycogen storage diseases and hepatic adenomatosis.

CLINICAL CASE

A 35 year-old woman without any significant past medical history, with a chief complaint that started in December 2012 with oppressive, mild intensity abdominal pain located in right upper quadrant in the abdomen on deep palpation. With an abdominal ultrasound showing a mass of 91×82×65cm located in the right flank, isoechogenic with internal vascularity. Contrast computed tomography scan showing an ovoid tumour with circumscribed borders, with heterogenic intense reinforcement and displacement of adjacent structures with dimensions of 88×71×80cm. In laparotomy, excision of the tumour and cholecystectomy with the trans surgical findings of an 8cm tumour with a pedicle containing one artery and one vein coming from the hepatic free border with strong adhesions to the gallbladder. Pathologic diagnosis: Extracapsular hepatic adenoma.

CONCLUSIONS

Incidence of hepatic adenomas has increased in the last decades, in a parallel fashion with the introduction of oral contraceptive pills, showing association with glycogen storage diseases and to a lesser degree with diabetes and pregnancy. Diagnosis is clinical with the aid of imaging studies. Prognosis of hepatic adenomas is not well established, therefore, management depends on symptoms, size, number, location and certainty of diagnosis.

Treatment of Hepatic Adenomatosis

Hepatic adenomatosis and hepatocellular adenomas share risk factors and the same pathophysiologic spectrum. The presence in the liver of 10 hepatocellular adenomas defines hepatic adenomatosis. The diagnosis may be established incidentally during a liver radiologic examination in the asymptomatic patient, or after associated right upper quadrant pain, hepatomegaly or liver test abnormalities. Upon the diagnosis of hepatic adenomatosis or either of its life-threatening complications - hemorrhage and progression to hepatocellular carcinoma - consideration should be given to potential medical, radiologic and surgical interventions including: observation (estrogens and androgens withdrawal), resection, transarterial embolization, radiofrequency ablation and liver transplantation. The management of patients with hepatic adenomatosis can be challenging. These patients should be ideally referred to centers with expertise in the management of liver diseases.

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.

Management of Hepatocellular Adenoma: Recent Advances

Hepatocellular adenoma (HCA) is a rare benign liver cell neoplasm that occurs more frequently in young women with a history of prolonged use of oral contraceptives. Surgical resection is considered because of the risk of hemorrhage in 25% and of malignant transformation in 5% of patients with HCA. HCA is a heterogeneous disease comprising 3 subtypes with distinct molecular and complication profiles. The inflammatory or telangiectatic subtype is at increased risk for hemorrhage, the β-catenin-activated subtype is at increased risk for malignant transformation, and the hepatocyte nuclear factor-1α-inactivated or steatotic subtype is at the least risk for complications. One-third of the patients with HCA have multiple tumors on imaging with no increased risk of complications. Magnetic resonance imaging is the modality of choice for the diagnosis and subtype characterization of HCA. Systematic resection of HCA is recommended in male patients owing to the higher incidence of malignant transformation, and surgical excision in women should be reserved for tumors 5 cm or larger associated with an increased risk of complications. Cessation of hormonal therapy and radiologic surveillance in women with HCA tumors smaller than 5 cm shows that the vast majority of HCA remain stable or undergo spontaneous regression. Percutaneous core needle biopsy is of limited value because the therapeutic strategy is based primarily on patient sex and tumor size. Transarterial embolization is the initial treatment for HCA complicated by hemorrhage. Pregnancy should not be discouraged in the presence of HCA, however, frequent sonographic surveillance is recommended.

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.

MR characterization of focal liver lesions: pearls and pitfalls

Magnetic resonance (MR) can characterize specific tissue subtypes, thus facilitating focal liver lesion diagnosis. Focal liver lesions that are isointense to hyperintense to liver on T1-weighted images are usually hepatocellular in origin. Chemical shift imaging can narrow the differential diagnosis by detecting the presence of lipid or iron. T2 and heavily T2-weigthed fast spin echo imaging can differentiate solid from nonsolid focal liver lesions. The authors illustrate these MR imaging pearls and the uncommon exceptions (pitfalls). The authors hope that you will find this less traditional contribution to the Magnetic Resonance Clinics of North America helpful in clinical practice.

Hepatic adenomatosis: a rare but important liver disease with severe clinical implications

A 56-year-old white female presented to the emergency room (ER) with acute onset of right upper quadrant abdominal pain, nausea, and vomiting, and she was found to have a sudden drop in hemoglobin. Abdominal computed tomography (CT) with and without intravenous contrast revealed multiple bilobar focal hepatic hypervascular lesions, one of them demonstrating spontaneous rupture with active intraperitoneal bleeding. A moderate hemoperitoneum was present. The patient underwent exploratory laparotomy for right hepatic posterior segmentectomy (right posterior sectionectomy) and peritoneal lavage. The histopathology evaluation revealed multiple liver adenomas. Hepatic adenomatosis is a clinical entity characterized by 10 or more hepatic adenomas. It must be distinguished from isolated hepatic adenoma as it bears a much higher risk of complications, such as spontaneous rupture, hemorrhage and malignant transformation. Here we discuss the radiologic and histopathologic findings of the current case along with a review of the English language medical literature.

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.

Liver adenomatosis: a rare indication for living donor liver transplantation

Liver adenomatosis (LA) is a rare benign disease of the liver with unclear pathogenesis, which is characterized by multiple hepatic adenomas. The management of LA remains controversial. Herein we have reported a case of LA treated by living donor liver transplantation (LDLT). A 48-year-old woman developed multiple liver adenomas. In view of the sizes and localizations of the lesions, the patient underwent right hepatic resection and segment II nodulectomy. Thirty-four months later, she developed recurrence of multiple hepatic adenomas and 2 nodules were highly suspect for hepatocellular carcinoma. Re-resection was not indicated due to the whole liver being involved with adenomas. The patient underwent LDLT. At 45 months thereafter she is alive and disease-free. In conclusion, LDLT is indicated in cases of nonresectability; it may offer optimal results in view of the absence of portal hypertension and the elimination of waiting list time.

Liver adenomatosis: serial investigation on MRI

PURPOSE

To describe the natural history of liver adenomatosis (LA), including complications and changes in lesion size over time.

MATERIALS AND METHODS

Eighteen patients with clinical diagnosis of LA were included. Clinical and biochemical information were collected. The initial and follow-up MR studies were reviewed retrospectively to determine change in lesion size and imaging features.

RESULTS

Seventeen patients were women (94.4%). The mean age of the initial MR study was 37.0 years (18-52 years). The median size of the largest lesion was 6.7 cm (range 3.0-13.5 cm). Intratumoral bleeding was detected on MRI in 9 lesions, in 7 patients (38.8%). The median size for hemorrhagic lesions was 7.6 cm (range 4.1-13.5 cm). During the mean follow-up period of 29.4 (range 4-98) months, 10 patients had stable disease (55.6%), and 8 patients had tumor regression (44.4%). Of 8 patients who were followed without intervention, 3 patients (37.5%) had spontaneous regression. No malignant transformation or lesion progression was occurred.

CONCLUSION

During an over 2-year follow-up period, the majority of lesions of LA appeared to remain stable or showed tumor regression. Spontaneous tumor regression can be observed in approximately 37% of individuals in the age range of 28-53 years.

MR imaging of benign focal liver lesions

Focal liver lesions (FLLs) are commonly encountered on routine imaging studies. Most lesions detected are benign, but many are indeterminate at the time of initial imaging. This article reviews the important role of MR imaging for the detection and characterization of various benign FLLs while illustrating typical imaging appearances and potential pitfalls in interpretation. The utility of diffusion-weighted imaging and hepatocyte-specific contrast agents is also discussed.

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.

Unusual uptake of 18FDG by a hepatic adenoma

Hepatic adenoma is a rare, benign tumor (with potential for malignant degeneration) and its diagnosis is difficult because its presentation is highly variable in medical imaging, particularly with MRI. In such cases, the use of a hepatic biopsy is usually recommended. (18)FDG-PET/CT provides a very significant predictive value for malignant hepatic lesions. In addition, the occurrence of an (18)FDG-avid benign tumor is a rare event. We hereby present the case of a patient with advanced breast cancer for whom an (18)FDG-PET/CT showed a focal hepatic uptake. A subsequent biopsy provided a diagnosis of a hepatic adenoma.

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.

Multiple hepatocellular adenomas in a patient with glycogen storage disease type I: various enhancement patterns in MRI with Gd-EOB-DTPA

The patient is a 20-year-old man with glycogen storage disease type I (GSD-type I). In his teens, multiple focal hepatic masses were detected on abdominal ultrasonography (US), which were diagnosed as multiple hepatocellular adenomas from the imaging. During follow-up, these masses had shown intermittent growth in size. In the evaluation of Gd-EOB-DTPA (gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid) MR imaging, these masses showed various signal intensities from hypo- to hyperintense during the hepatocyte-specific phase. Intermittent growth and elevation of serum PIVKA-II levels indicate the potential for malignant transformation, so the patient underwent partial hepatectomy. The resected masses were all consistent with benign hepatocellular adenomas histopathologically.

"Incidentaloma" of the liver: management of a diagnostic and therapeutic dilemma

The continuous development of highly sensitive clinical imaging increased the detection of focal lesions of the liver. These accidentally detected liver tumors without liver-specific symptoms such as cholestasis have been named “incidentalomas.” Diagnostic tools such as sonography, computed tomography, or magnetic resonance imaging are used increasingly in asymptomatic individuals without defined suspected diagnoses in the setting of general prevention or followup after a history of malignancy. But despite continuous improvement of diagnostics, some doubt regarding the benign or malign behavior of a tumor remains. In case an asymptomatic hemangioma or FNH can be preoperatively detected with certainty, the indication for surgery must be very strict. In case of symptomatic liver lesions surgical resection should only be indicated with tumor-specific symptoms. In the remaining cases of benign lesions of the liver, a “watch and wait” strategy is recommended. In case of uncertain diagnosis, especially in patients with positive history of a malignant tumor or the suspected diagnosis of hepatocellular adenoma, surgical resection is indicated. Due to the continuous improvement of surgical techniques, liver resection should be done in the laparoscopic technique. Laparoscopic surgery has lower morbidity and shorter hospitalization than open technique.

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.

Aetio-pathogenesis and the management of spontaneous liver bleeding in the West: a 16-year single-centre experience

BACKGROUND

Spontaneous liver bleeding (SLB) is a rare but potentially fatal complication. In contrast to the East, various benign pathologies are the source of SLB in the West. An accurate diagnosis and a timely implementation of appropriate treatment are crucial in the management of these patients. The present study presents a large Western experience of SLB from a specialist liver centre.

METHODS

A retrospective analysis of patients presented with SLB between January 1995 and January 2011.

RESULTS

Sixty-seven patients had SLB, 44 (66%) were female and the median age at presentation was 47 years. Abrupt onset upper abdominal pain was the presenting symptom in 65 (97%) patients. The aetiology for SLB was hepatic adenoma in 27 (40%), hepatocellular carcinoma (HCC) in 17 (25%) and various other liver pathologies in the rest. Emergency treatment included a conservative approach in 42 (64%), DSA and embolization in 6 (9%), a laparotomy and packing in 6 (9%) and a liver resection in 11 (16%) patients. Eleven (16%) patients had further planned treatments. Seven (10%) died during the same admission but the mortality was highest in patients with HELLP syndrome. At a median follow-up of 54 months all patients with benign disease are alive. The 1-, 3- and 5-year survival of patients with HCC was 59%, 35% and 17%, respectively.

CONCLUSION

SLB is a life-threatening complication of various underlying conditions and may represent their first manifestation. The management should include initial haemostasis followed by appropriate staging investigations to provide a definitive treatment for each individual patient.

[Benign focal hepatic lesions]

A profound knowledge of the various benign focal hepatic lesions and selection of the most suitable radiological examination modality is essential for achieving an accurate characterization of a hepatic lesion and in turn will determine the further patient management. This will avoid unnecessary agitation to both patient and the referring clinician and limits time-consuming, costly and risky biopsies to an absolute minimum. The following article will discuss the typical and atypical appearances of the most frequent and clinically relevant benign focal hepatic lesions with ultrasound, computed tomography and magnetic resonance imaging.

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.

Bland embolization in the treatment of hepatic adenomas: preliminary experience

The study presents preliminary, retrospective experience with bland embolization for hepatic adenomas (HAs) with the use of tris-acryl gelatin microspheres. Eight patients underwent bland embolization for biopsy-proven HAs. A biopsy specimen was taken from only one lesion when multiple lesions were present. Seventeen embolizations were performed for abdominal pain, active bleeding, or prophylaxis against bleeding. Five patients underwent multiple procedures. Technical success rate was 100%. Median follow-up was 24 months (range, 10-40 mo). No growth was observed at follow-up in any treated lesion, and many lesions (13 of 16) regressed. Bland embolization may be safely used for treatment of abdominal pain and bleeding from HAs.

Current imaging strategies of primary and secondary neoplasms of the liver

This article details the diagnosis and imaging of primary and secondary neoplasms of the liver. Benign conditions that can mimic malignancy are also discussed, such as focal nodular hyperplasia and adenoma. Considerable attention is given to hepatoma, which is the most common primary hepatic tumor in the United States. The roles of magnetic resonance imaging, computed tomography, and ultrasound are evaluated, with recommendations for their effective use. Pitfalls in imaging related to posttreatment changes and unusual patterns of metastatic disease are illustrated.

Solid hypervascular liver lesions: accurate identification of true benign lesions on enhanced dynamic and hepatobiliary phase magnetic resonance imaging after gadobenate dimeglumine administration

PURPOSE

To evaluate hepatobiliary phase magnetic resonance imaging with gadobenate dimeglumine for differentiation of benign hypervascular liver lesions from malignant or high-risk lesions.

METHODS AND MATERIALS

Retrospective assessment was performed of 550 patients with 910 hypervascular lesions (302 focal nodular hyperplasia [FNH], 82 nodular regenerative hyperplasia [NRH], 59 hepatic adenoma or liver adenomatosis [HA/LA], 329 hepatocellular carcinomas [HCC], 12 fibrolamellar-HCC [FL-HCC], 21 peripheral cholangiocarcinomas [PCC], 105 metastases). Imaging was performed before and during the arterial, portal-venous, equilibrium, and hepatobiliary phases after gadobenate dimeglumine administration (0.05 mmol/kg). Histologic confirmation was available for ≥1 lesion per patient, except for patients with suspected FNH (diagnosis based on characteristic enhancement/follow-up). Lesion differentiation (benign/malignant) on the basis of contrast washout and lesion enhancement (hypo-/iso-/hyperintensity) was assessed (sensitivity, specificity, accuracy, PPV, and NPV) relative to histology or final diagnosis.

RESULTS

On portal-venous or equilibrium phase images, washout was not seen for 208 of 526 (39.5%) malignant (HCC, FL-HCC, PCC, metastases) and high-risk (HA/LA) lesions. Conversely, only 5 of 384 (1.3%) true benign lesions (FNH/NRH) showed washout. Taking washout as indicating malignancy, the sensitivity, specificity, and accuracy for malignant lesion identification during these phases was 61.8%, 98.7%, and 77.4%. On hepatobiliary phase images, 289 of 302 FNH, 82 of 82 NRH, 1 of 59 HA or LA, 62 of 341 HCC or FL-HCC, and 2 of 105 metastases were hyperintense or isointense. Taking iso- or hyperintensity as an indication for lesion benignity, the sensitivity, specificity, accuracy, PPV, and NPV for benign lesion identification was 96.6%, 87.6%, 91.4%, 85.1%, and 97.3%, respectively.

CONCLUSIONS

Hepatobiliary phase imaging with gadobenate dimeglumine is accurate for distinguishing benign lesions from malignant or high-risk lesions. Biopsy should be considered for hypointense lesions on hepatobiliary phase images after gadobenate dimeglumine.

Incidental Findings: A Case Study of Benign Liver Masses

Frequently, liver masses are found in the course of medical imaging examinations. This article presents a unique case study with multiple benign liver masses: hemangiomas, focal nodular hyperplasias (FNHs), and liver cell adenomas (LCAs). Most hemangiomas have a characteristic echogenic appearance on sonography and need no further workup. FNH may be difficult to visualize sonographically because it is composed of normal hepatocytes in an abnormal arrangement. LCAs and liver adenomatosis are more serious, requiring medical intervention and monitoring.

Tumors of the liver and intrahepatic bile ducts: radiologic-pathologic correlation

Primary tumors of the liver can be classified pathologically based on their cell of origin into epithelial tumors, arising from hepatocytes or biliary epithelium, and nonepithelial tumors, including mesenchymal tumors and lymphoma. Characteristic findings on MR imaging can be seen in many cases. This article reviews the MR imaging appearance of these tumors with pathologic correlation.

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.

Hepatic adenomatosis in a 7-year-old child treated earlier with a Fontan procedure

Patients who undergo a Fontan procedure experience some degree of liver disease. Hemodynamic changes such as central venous hypertension, depressed dynamic cardiac output, and late ventricular dysfunction combined with long-standing hypoxia preceding the Fontan procedure all are recognized risk factors for hepatic injury. The histopathologic changes associated with cardiac hepatopathy include chronic passive congestion, centrilobular necrosis, and cardiac cirrhosis. However, hepatic adenoma and hepatic adenomatosis (HA) are not well-known pathologies during the course of cardiac hepatopathy. This study focused on a 7-year-old girl with chronic hepatic changes and HA who had undergone a Fontan procedure. Hepatic adenomatosis was diagnosed on the basis of magnetic resonance imaging (MRI) and MRI-guided liver biopsy. To the best of the authors' knowledge, this case involved the youngest patient with hepatocellular adenomatosis documented in the literature. It was a unique case because the patient experienced HA after a Fontan procedure.