Biologic and clinical features of benign solid and cystic lesions of the liver

ACG Clinical Guideline: Focal Liver Lesions

Focal liver lesions (FLLs) have become an increasingly common finding on abdominal imaging, especially asymptomatic and incidental liver lesions. Gastroenterologists and hepatologists often see these patients in consultation and make recommendations for management of multiple types of liver lesions, including hepatocellular adenoma, focal nodular hyperplasia, hemangioma, and hepatic cystic lesions including polycystic liver disease. Malignancy is important to consider in the differential diagnosis of FLLs, and healthcare providers must be familiar with the diagnosis and management of FLLs. This American College of Gastroenterology practice guideline uses the best evidence available to make diagnosis and management recommendations for the most common FLLs.

Imaging features and management of focal liver lesions

Notably, the number of incidentally detected focal liver lesions (FLLs) has increased dramatically in recent years due to the increased use of radiological imaging. The diagnosis of FLLs can be made through a well-documented medical history, physical examination, laboratory tests, and appropriate imaging methods. Although benign FLLs are more common than malignant ones in adults, even in patients with primary malignancy, accurate diagnosis of incidental FLLs is of utmost clinical significance. In clinical practice, FLLs are frequently evaluated non-invasively using ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Although US is a cost-effective and widely used imaging method, its diagnostic specificity and sensitivity for FLL characterization are limited. FLLs are primarily characterized by obtaining enhancement patterns through dynamic contrast-enhanced CT and MRI. MRI is a problem-solving method with high specificity and sensitivity, commonly used for the evaluation of FLLs that cannot be characterized by US or CT. Recent technical advancements in MRI, along with the use of hepatobiliary-specific MRI contrast agents, have significantly improved the success of FLL characterization and reduced unnecessary biopsies. The American College of Radiology (ACR) appropriateness criteria are evidence-based recommendations intended to assist clinicians in selecting the optimal imaging or treatment option for their patients. ACR Appropriateness Criteria Liver Lesion-Initial Characterization guideline provides recommendations for the imaging methods that should be used for the characterization of incidentally detected FLLs in various clinical scenarios. The American College of Gastroenterology (ACG) Clinical Guideline offers evidence-based recommendations for both the diagnosis and management of FLL. American Association for the Study of Liver Diseases (AASLD) Practice Guidance provides an approach to the diagnosis and management of patients with hepatocellular carcinoma. In this article, FLLs are reviewed with a comprehensive analysis of ACR Appropriateness Criteria, ACG Clinical Guideline, AASLD Practice Guidance, and current medical literature from peer-reviewed journals. The article includes a discussion of imaging methods used for the assessment of FLL, current recommended imaging techniques, innovations in liver imaging, contrast agents, imaging features of common nonmetastatic benign and malignant FLL, as well as current management recommendations.

A preliminary study on the establishment of a cyst and cystic neoplasm tissue-mimicking model

Context

The present experimental models of cystic diseases are not adequate and require further investigation.

Aim

In this study, a new way of producing a tissue-mimicking model of cysts and cystic neoplasms was evaluated.

Settings and Design

To simulate cysts and cystic neoplasms, ex vivo rabbit normal bladders and VX2-implanted tumor bladders were produced, fixed, and embedded in agarose gel.

Methods and Materials

The samples were classified into four groups based on tumor features and the maximal transverse diameter of the rabbit bladder, which were assessed using computer tomography (CT) imaging and statistically analyzed.

Statistical Analysis Used

Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) software. The t-test was used for analyzing enumeration data.

Results

Twenty-one rabbit bladders (21/24) were successfully removed and prepped for this experiment, comprising eleven normal bladders (11/24) and ten implanted with VX2 tumors (10/24). The gelling ingredient used to form the visualization and fixation matrix was agarose at a concentration of 4 g/200 mL. The temperature of the agarose solution was kept constant at 40-45°C, which is the optimal temperature range for ex vivo normal bladder and implanted VX2 tumor bladder insertion. The average time required to embed and fix the bladders in agarose gel was 45.0 ± 5.2 minutes per instance. The gel-fixing matrix's strength and light transmittance were enough for building the models.

Conclusion

We created an experimental tissue-mimicking model of cysts and cystic neoplasms with stable physicochemical features, a safe manufacturing method, and high repeatability. These models may be used to assist with cystic lesion diagnosis and treatment techniques.

Non-invasive diagnosis and follow-up of benign liver tumours

Hepatocellular benign liver tumours are mainly developed on normal liver and include hepatic hemangioma, focal nodular hyperplasia and hepatocellular adenoma from the most frequent to the less frequent. The diagnosis of hepatic hemangioma and of simple hepatic biliary cysts can be performed using non-invasive criteria using liver ultrasonography or contrast enhanced MRI. Most of the time the diagnosis of focal nodular hyperplasia can be achieved using contrast-enhanced ultrasonography or contrast enhanced MRI with an additional value of hepatobiliary contrast-agent in this setting. Rarely, if a doubt persists, a tumour and non-tumour liver biopsy can be required in order to establish the diagnosis. As hepatic hemangioma, simple hepatic biliary cysts and focal nodular hyperplasia are not associated with complications, they don't require any treatments or follow-up. Hepatocellular adenomas are mainly diagnosed at histology on surgical samples or liver biopsy even if some radiological features are highly suggestive of several subtypes of hepatocellular adenomas. Finally, the management of hepatocellular adenomas should be guided according to the tumour size, gender but also to the molecular subtypes.

Significance of hepatocyte atypia in liver fine needle aspiration

Fine needle aspiration (FNA) of the liver is frequently the diagnostic procedure of choice for sampling hepatic lesions. One of the main diagnostic challenges in the interpretation of liver FNA is distinguishing dysplastic lesions and well-differentiated hepatocellular carcinoma (WD-HCC) from benign processes, as they share significant cytomorphologic overlap. Furthermore, the diagnosis of HCC often requires evaluation of stroma for invasion, which may not be present on cytology and small needle biopsy specimens. A reporting system for liver cytopathology has yet to be instituted. Without standardized and well-defined criteria for hepatocyte atypia, we recommend limiting the use of atypia in evaluation of liver FNA specimens to describe a diagnosis of exclusion, in which all known benign and neoplastic processes have been ruled out. The cytologic findings on the FNA of a liver nodule may be best reported as atypical hepatocytes in the absence of a core needle biopsy or cell block sufficient to render a definitive diagnosis of HCC.

Benign Liver Tumors

Background

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

Summary

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

Key Message

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

Focal Nodular Hyperplasia and Hepatic Adenoma: Evaluation and Management

Focal nodular hyperplasia and hepatocellular adenoma are benign liver lesions that occur most frequently in women and may be found as incidental findings on imaging. hepatocellular adenomas may be infrequently associated with malignant progression or risk of rupture and as such, require surveillance or definitive treatments based on their size threshold. It is important clinically to differentiate these lesions, and utilizing imaging modalities such as contrast enhanced ultrasound or magnetic resonance imaging can be helpful in diagnosis. Further molecular subtyping of hepatocellular adenoma lesions may be beneficial to describe risk factors and potential future clinical complications.

Pulmonary embolism due to hemangioma of segment I compressing the inferior vena cava: A Case Report

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Compression of the Vena cava leading to pulmonary embolism is a rare symptom of hemangioma.

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Resection of Hemangioma to normalize the flow of the vena cava is a rare indication, but an effective and safe therapy.

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The patient required no anticoagulation after the surgery.

Introduction

Hemangiomas are common hepatic lesions and are mostly asymptomatic. Operative removal should only be performed when the lesions are symptomatic, and removal of the hemangioma is deemed to be more beneficial than the risk of the operation itself.

Presentation of the case

The multiple hemangiomas of our patient were discovered nine years before first symptoms. The patient presented with pulmonary artery embolism due to a compression of the vena cava inferior by a hemangioma in segment I. No other cause of thromboembolic events could be diagnosed. We performed surgical enucleation of the hemangioma, which resulted in the normalization of blood flow in the inferior vena cava. As the inducing factor for clot development was removed, no permanent thrombosis prophylaxis was implicated.

Discussion

Pulmonary embolisms owing to compression of the inferior vena cave are rare.

Conclusion

Until now to our knowledge, pulmonary embolisms have never been described as an indication for hepatic hemangioma enucleation.

Benign Hepatic Tumors: From Incidental Imaging Finding to Clinical Management

Benign hepatic tumors (BHTs) are commonly detected as incidental finding mainly due to the frequent utilization of imaging modalities, including ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Rigorous clinical evaluation, with a particular focus on chronic liver disease (CLD) or risk factors for CLD, medication history, physical examination for signs of CLD, blood tests, and a review of past liver radiology constitute the initial steps in the evaluation of a new liver lesion. Further, contrast-enhanced imaging using US, CT and MRI, can be used depending on the clinical scenario and their availability. The contrast-enhanced MRI provides detailed tissue assessment while avoiding exposure to radiations, although it is scarcely available and expensive. While the liver tissue-specific protocols ensure precise diagnosis, a biopsy is recommended in selected or doubtful cases. Further, most BHTs, such as hemangiomas, are harmless and do not require special management or follow-up, the hepatic adenomas and large or atypical cases of focal nodular hyperplasia are clinically relevant and require management/follow-up. In such cases, it is favorable to have a multidisciplinary team approach, which includes hepatologist, radiologist, hepatobiliary surgeon, and pathologist. This review aims to elaborate the current understanding of BHTs, and provide a practical guidance for primary care and practitioners of family and internal medicine for the disease evaluation and management.

The management of a cystic hepatic lesion ruptured in the bile ducts: a case report

Background

Hepatic cystadenoma is a rare benign cystic tumor; it tends to recur after incomplete surgical resection and has malignant potential. We report the case of a patient with a ruptured biliary cystadenoma in the common bile duct that caused diagnostic and therapeutic problems.

Case presentation

A 34-year-old North African woman, admitted for angiocholitis, was operated 2 months before for a hepatic cystic lesion taken for a hydatid cyst compressing her common bile duct. The clinical and the complementary examinations converged toward recurrence of the hydatid cyst for which a surgical resection was decided. Intraoperative findings as well as the histological study of the “membranes” extracted from her common bile duct indicated a hepatic cystadenoma.

Conclusions

The rarity of hepatic cystadenoma and the non-specificity of clinical and imaging signs make diagnosis of hepatic cystadenoma difficult, especially when it is complicated by rupture in the bile ducts; this contributes to a delay in diagnosis and an inadequate therapeutic approach.

An unusual case of left hepatectomy for Focal Nodular Hyperplasia (FNH) linked to the use of Anabolic Androgenic Steroids (AASs)

INTRODUCTION

Focal Nodular Hyperplasia (FNH) is the second most common benign tumor of the liver. Clinically FNH is asymptomatic and discovered incidentally . The pathogenesis is unclear; FNH is usually asymptomatic. When the tumor is large, it may be painful. Surgery is recommended only in the case of complications such as compression of adjacent organs, lesion progression with tumor size >5cm and presence of symptoms.

PRESENTATION OF CASE

A 30 years old man, was evaluated during a routine visit, for diffuse abdominal pain and weight loss; Abdominal ultrasound showed no evidence of biliary obstruction but the US shows a hypoechoic, well defined focal lesion in the left liver. For a more accurate diagnosis a Magnetic Resonance detected a focal area about 14×9 cm in diameter, hypointense. Liver biopsy was not done.We could not diagnose it definitively as FNH from the results of imaging studies; so for the size of symptomatic lesion, the undefined diagnosis of FNH ,and due to the great increase in the size of the mass located in the left lobe, during such a short period , the surgery was been recommended.

DISCUSSION

FNH is the second most common hepatic lesion, but clinically relevant cases of FNH are rare with a reported prevalence in US studies of 0,03%. In our case the young patient was taking dietary supplements including anabolic androgenic steroids (AASs), carnitine and l-arginine.

CONCLUSION

The particularity of our case is the increasing of the lesion in two years in which the patient made use of anabolic steroids. under use of . This could be the explanation for increasing of nodule.

Diagnosis and treatment of benign liver nodules: Brazilian Society of Hepatology (SBH) recommendations

Space-occupying lesions of the liver may be cystic or solid. Ultrasonography is an extremely useful method for initial screening, and suffices for diagnosis of simple hepatic cysts. Complex cysts and solid masses require computed tomography or magnetic resonance imaging for confirmation. Wide surgical excision is indicated in cystadenoma or cystadenocarcinoma. Clinical and epidemiological data are important, as nodules in noncirrhotic livers are more likely to be benign. Hemangiomas, the most common benign tumors, require no follow-up after diagnostic confirmation if they are small and asymptomatic. Patients with giant, symptomatic hemangiomas or compression of adjacent structures should be referred to hepatobiliary centers for potential surgery. The genetic heterogeneity of hepatocellular adenomas and their epidemiology and prognosis prompted classification of these tumors into four subtypes based on histology and immunohistochemistry. The major complications of hepatocellular adenomas are rupture with bleeding and malignant transformation. Rupture occurs in approximately 30% of cases. The main risk factors are tumors size >5 cm and inflammatory subtype. Hepatocellular adenomas may enlarge during pregnancy due to marked hormonal stimulation. As oral contraceptive pills and anabolic steroids have associated with hepatocellular adenomas growth, particularly of the hepatocyte nuclear factor-1alfa subtype, these drugs should be discontinued. Focal nodular hyperplasia is the second most common benign tumor of the liver. It is most frequent in women aged 20 to 60, and 70% to 90% of cases are asymptomatic. In the absence of a central scar and/or other hallmarks of Focal nodular hyperplasia, with uncertainty between this diagnosis and hepatocellular adenoma, liver-specific contrast agents are indicated.

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.

Preserved or enhanced OATP1B3 expression in hepatocellular adenoma subtypes with nuclear accumulation of β-catenin

AIM

Recent studies have indicated that hepatocellular adenoma (HCA) is a heterogenous group of benign tumors with various genetic and clinicopathological characteristics. We delineated the clinicopathological characteristics of HCA subtypes and evaluated the expression of transporter protein OATP1B3 in HCA.

METHODS

HCA in 34 Japanese patients were investigated immunohistochemically and classified into four subtypes (HNF1α-inactivated type, H-HCA; β-catenin-activated type, b-HCA; inflammatory type, I-HCA; unclassified type, u-HCA). Immunostaining of OATP1B3 protein in HCA tissue sections was performed to determine the association between OATP1B3 expression and HCA subtypes.

RESULTS

HCA was categorized into the following four subtypes and two combined subtypes: 10 H-HCA (29%), 10 I-HCA (29%), seven b-HCA (21%), two b-HCA/H-HCA (6%), two b-HCA/I-HCA (6%) and three u-HCA (9%). The male-to-female ratio was 18:16. Oral contraceptive use was rare but seven HCA were found in patients with glycogen storage disease, congenital absence of the portal vein and idiopathic portal hypertension. OATP1B3 expression was decreased in 24 HCA but was preserved or increased in 10 HCA. All nine HCA with nuclear staining for β-catenin showed preserved or enhanced OATP1B3 expression, indicating a significant association between nuclear β-catenin accumulation and OATP1B3 expression in HCA.

CONCLUSION

HCA subtype classification was validated in 91% of our Japanese subjects although their clinical backgrounds including rare contraceptive use were different from European subjects. A close association between preserved or enhanced OATP1B3 expression and b-HCA subtype indicated important modalities for clinical decisions in the treatment and follow up of patients with HCA.

National trends in the use of surgery for benign hepatic tumors in the United States

BACKGROUND

The widespread use of diagnostic imaging has led to an increase in the incidence and diagnosis of benign liver tumors. The objective of this study was to define the overall use and temporal trends of operative procedures for benign liver tumors using a nationally representative cohort.

METHODS

All patients who underwent liver surgery for benign liver tumors between 2000 and 2011 were identified from the Nationwide Inpatient Sample database. Trends in annual volume of liver procedures were analyzed using the average annual percent change (AAPC) assessed by joinpoint analysis.

RESULTS

There were 2,489 open (94.5%) and 144 (5.5%) minimally invasive surgical (MIS) procedures. Partial hepatectomy accounted for 43.8% of all cases (n = 1,153). Surgery for patients with benign liver tumors increased from 156 in 2000 to 272 in 2011 (AAPC, 5.8%; 95% CI, 3.2-8.6%). There was decline in the relative use of open operative procedures from 98.1% in 2000 to 92.3% in 2011 (AAPC, -0.4%; 95% CI, -0.7 to -0.1%). In contrast, the proportion of MIS procedures increased from 1.9% in 2000 to 7.7% in 2011 (AAPC, 7.4%; 95% CI, 1.9-13.3%). The median duration of stay among all patients was 5 days (interquartile range, 4-7; 5 days [open] vs 3 days [MIS]; P < .001). Inpatient mortality was 0.6% (n = 15 [open] vs n = 0 [MIS]; P = .43) and did not change during the study period (P > .05).

CONCLUSION

Overall volume of surgical management of benign liver tumors has increased substantially over the past decade. There has been a relative shift away from open procedures toward MIS procedures.

A case of progressing focal nodular hyperplasia and its molecular expression pattern

We report the case of an adult male with progressing focal nodular hyperplasia (FNH). Although imaging studies suggested that the tumor was a classical FNH, the tumor biopsy showed glutamine synthetase expression and heat shock protein 70 in part of the tumor. As we could not definitely distinguish this case of FNH from early hepatocellular carcinoma (HCC), we performed laparoscopic partial hepatectomy. The surgical resected specimen showed that the tumor had a central scar with vascular and cholangiolar proliferation, which is compatible with FNH. Immunohistochemical analysis showed that the molecular expression pattern was compatible with FNH in the center of the tumor, whereas it partly resembled early HCC in the periphery of the tumor. FNH progression is occasionally found, and the molecular pattern of the progressing area in FNH might resemble that of early HCC due to morphologic and phenotypic changes induced by the regenerative mechanism and the alteration of blood flow. We should carefully observe progressing FNH.

Hepatocellular benign tumors-from molecular classification to personalized clinical care

Focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) are benign hepatocellular tumors that develop most frequently in women without cirrhosis. Genomic approaches have identified signaling pathways related to these benign hepatocyte proliferations. FNH, a polyclonal lesion, is characterized by local vascular abnormalities and heterogeneous activation of Wnt/β-catenin and transforming growth factor β signaling. Four major subgroups of HCAs have been identified based on mutations in specific oncogenes and tumor suppressor genes. Each molecular subtype of HCA has been associated with specific pathways, providing new information about benign tumorigenesis. Key features include metabolic alterations (induced by defects in HNF1A), oncogene-induced inflammation (activation of JAK-STAT signaling in inflammatory adenomas), and an association between activation of Wnt/β-catenin signaling and progression of HCAs in hepatocellular carcinomas. Benign hepatocellular tumors can be classified using immunohistochemical analyses. Studies of genotypes and phenotypes of FNH and HCAs have led to the identification of risk factors and improved invasive and noninvasive diagnostic techniques, evaluation of prognosis, and treatment. We review the molecular pathways involved in benign hepatocyte proliferation and discuss how this basic knowledge has been progressively translated into personalized clinical care.

Clinical features and natural history of hepatocellular adenomas: the impact of obesity

BACKGROUND

Hepatocellular adenoma is a benign tumour associated with bleeding and malignant transformation. Obesity has been linked to hepatic tumourigenesis.

AIM

To evaluate the presentation of hepatocellular adenoma in obesity, and the impact of obesity on the clinical course.

METHODS

Records of 60 consecutive patients (between 2005 and 2010) with a diagnosis of hepatocellular adenoma from a single tertiary centre were analysed.

RESULTS

Fifty six of 60 patients were women, median age was 36years, 75% had history of contraceptive use, 18% were overweight and 55% were obese (BMI ≥30kg/m(2) ). Majority (63%) were asymptomatic; seven patients presented with bleeding. Single (28%) and multiple adenomas (72%) were encountered; size ranged from 1 to 19.7cm. Obesity was more often associated with multiple adenomas (85% vs. 48%, P=0.005), bilobar distribution (67% vs. 33%, P=0.01), lower serum albumin (P=0.007) and co-morbidities of fatty liver (P=0.006), diabetes (P=0.003), hypertension (P=0.006) and dyslipidemia (P=0.03). During median follow-up of 2.6years, there were no instances of bleeding, malignant transformation or death. Thirty four patients underwent therapeutic intervention (17 surgical resection, nine transarterial embolization and eight both interventions sequentially). The rate of complete resection of adenoma(s) was significantly lower in obese patients (8% vs. 69%, P=0.004). In the 26 patients without intervention, tumour size progression was more frequently observed in obese patients (33% vs. 0%, P=0.05). Three of 15 obese patients (20%) lost ≥5% body weight and there was no progression in the liver lesions.

CONCLUSIONS

Obesity and features of metabolic syndrome were frequently observed in hepatocellular adenoma. Multiple and bilobar adenomas were more frequent in obese patients. Among patients who were conservatively managed, tumour progression was more often associated with obesity.