Laparoscopic hepatectomy for hepatocellular adenoma using the hepatic vein as anatomic markers,How I do it.(with video)

TECHNIQUE

Hepatocellular adenoma (HCA) is a benign monoclonal tumour that originates from mature hepatocytes.Liver resection is recommended in case of overt malignant transformation to hepatocellular carcinoma.However, hepatobiliary surgeries are technically challenging in patients with giant HCA (GHCA) owing to the risk of catastrophic intraoperative bleeding and difficulty with its control during laparoscopic treatment. We present a technical note on the utilization of the hepatic vein as anatomical landmarks for laparoscopic removal of giant hepatic glands, without intraoperative ultrasonography and with the aid of an augmented reality navigation system during surgery.

RESULTS

This video shows aA 37-year-old man was recommended treatment for a progressively increasing HCA (from 3 to 10 cm in a year) involving the right hepatic vein (RHV), inferior vena cava (IVC) and middle hepatic vein (MHV), resulting in the invisibility of the above intrahepatic anatomic markers in CT. Laparoscopic hepatectomy was performed using the hepatic vein as anatomic markers in a treatment centre specialising in minimally invasive surgeries. The procedure involved fully mobilising the right liver, transecting the parenchyma along the demarcation line in the caudal-to-cranial direction, exposing the involved caudal MHV, isolating and transecting the involved RHV and preserving the integrity of the involved IVC.

CONCLUSIONS

Laparoscopic hepatectomy for intractable GHCA using the involved intrahepatic anatomic markers is feasible and effective. It reduces pre-operative haemorrhage and open conversion rates while maximising postoperative hepatic function.

Indocyanine green (ICG)-guided robotic resection for liver adenoma: combined technologies for precision surgery

HCA resection is crucial to prevent bleeding and malignant transformation. The aim of this study was to enhance the precision of tumor resection in hepatocellular adenoma (HCA) through the combination of intraoperative ultrasound (IOUS) and indocyanine green (ICG) fluorescence imaging. ICG was intravenously injected 24 h before surgery, enabling positive staining of HCA nodules. IOUS guided the parenchymal transection performed using the RoboLap approach. IOUS combined with ICG effectively demarcated lesions, allowing precision surgery while sparing healthy liver tissue. Intraoperative frozen examination further validated the potential of ICG to identify previously undetected lesions. The study showed promising advantages of ICG in HCA resections, potentially reducing the risk of recurrence and malignant transformation. The combined robotic and laparoscopic approach improved the feasibility of parenchymal-sparing surgery, offering a cautious assessment of HCA lesions.

Patient with a novel syndrome with multiple benign hepatic lesions and extrahepatic neoplasms

Simultaneous occurrence of benign hepatic lesions of different types is a sporadic phenomenon. To the best of our knowledge, we report the first clinical case of a syndrome with simultaneous manifestations of three different entities of benign liver tumors (hepatocellular adenoma, focal nodular hyperplasia and hemangioma) with a novel mutation detected in the liver adenoma and in the presence of a number of further extrahepatic organ neoplasms. Furthermore, we describe for the first time the presence of liver epithelial cells of hepatocytic phenotype expressing cytokeratin 7 (CK7) at the border of the adenoma. These findings may be important for explaining pathogenesis of benign as well as malignant tumors based on genetic and histopathological features.

Hepatic adenoma: evolution of a more individualized treatment approach

BACKGROUND

Hepatic adenomas (HAs) are benign, solid liver lesions, which carry a risk of hemorrhage and malignant transformation. This review article highlights the advances in the diagnosis and management of HAs.

METHODS

A comprehensive review was performed using MEDLINE/PubMed and Web of Science databases with a search period ending on September 30, 2023. Using PubMed, the terms "hepatocellular," "hepatic," and "adenoma" were searched.

RESULTS

HA has been classified into at least 8 subtypes based on molecular pathology, each exhibiting unique histopathologic features, clinical considerations, and risk of malignant transformation. The most common subtype is inflammatory HA, followed by hepatocyte nuclear factor 1α-inactivated HA, β-catenin exon 3-mutated HA (βex3-HA), β-catenin exon 7- or 8-mutated HA, sonic hedgehog HA, and unclassified HA. Magnetic resonance imaging is the best imaging method for diagnosis and can distinguish among HA subtypes based on fat and telangiectasia pathologic characteristics. The risk of malignant transformation varies among molecular subtypes, ranging from <1% to approximately 50%. Up to 42% of HAs present with spontaneous intratumoral hemorrhage and peritoneal hemorrhage. In general, only 15% to 20% of patients require surgery. HA larger than 5 cm are more likely to be complicated by bleeding and malignant transformation, regardless of subtype, and should generally be resected. In particular, βex3-HA carries a high risk of malignant transformation and can be considered a true precancerous lesion.

CONCLUSION

The management of HAs is based on a multidisciplinary approach. Clinical decision-making should integrate information on gender, tumor size, and HA subtyping. In the future, patients with HA will benefit from novel medical therapies tailored to the individual molecular subtypes.

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.

The contribution of ultrasound in the diagnostic pathway of a symptomatic hepatocellular adenoma arising from ectopic liver

Ectopic liver (EL) is a rare congenital anomaly characterized by the presence of a mass composed of hepatic tissue localized in a different anatomical location with no connection to the native liver. Usually an incidental finding, EL can rarely cause symptoms such as abdominal pain due to torsion, intraperitoneal bleeding, compression, obstruction, or neoplastic transformation, both benign and malignant. EL is often suspected after instrumental investigations such as ultrasound, CT and MRI, however a definitive diagnosis is necessarily bioptic. Here we report a case of a 22-year-old Italian female patient with acute abdominal pain, who underwent abdominal ultrasound, CEUS with Sonovue®, CT scan and ultrasound-guided biopsy which raised the suspicion of hepatocellular adenoma (H-HCA). After a laparoscopic excision of the lesion a diagnosis of H-HCA was formulated.

Spatial characterisation of β-catenin-mutated hepatocellular adenoma subtypes by proteomic profiling of the tumour rim

Background & Aims

Hepatocellular adenomas (HCAs) are rare, benign, liver tumours classified at the clinicopathological, genetic, and proteomic levels. The β-catenin-activated (b-HCA) subtypes harbour several mutation types in the β-catenin gene (CTNNB1) associated with different risks of malignant transformation or bleeding. Glutamine synthetase is a surrogate marker of β-catenin pathway activation associated with the risk of malignant transformation. Recently, we revealed an overexpression of glutamine synthetase in the rims of exon 3 S45-mutated b-HCA and exon 7/8-mutated b-HCA compared with the rest of the tumour. A difference in vascularisation was found in this rim shown by diffuse CD34 staining only at the tumour centre. Here, we aimed to characterise this tumour heterogeneity to better understand its physiopathological involvement.

Methods

Using mass spectrometry imaging, genetic, and proteomic analyses combined with laser capture microdissection, we compared the tumour centre with the tumour rim and with adjacent non-tumoural tissue.

Results

The tumour rim harboured the same mutation as the tumour centre, meaning both parts belong to the same tumour. Mass spectrometry imaging showed different spectral profiles between the rim and the tumour centre. Proteomic profiling revealed the significant differential expression of 40 proteins at the rim compared with the tumour centre. The majority of these proteins were associated with metabolism, with an expression profile comparable with a normal perivenous hepatocyte expression profile.

Conclusions

The difference in phenotype between the tumour centres and tumour rims of exon 3 S45-mutated b-HCA and exon 7/8-mutated b-HCA does not depend on CTNNB1 mutational status. In a context of sinusoidal arterial pathology, tumour heterogeneity at the rim harbours perivenous characteristics and could be caused by a functional peripheral venous drainage.

Impact and implications

Tumour heterogeneity was revealed in β-catenin-mutated hepatocellular adenomas (b-HCAs) via the differential expression of glutamine synthase at tumour rims. The combination of several spatial approaches (mass spectrometry imaging, genetic, and proteomic analyses) after laser capture microdissection allowed identification of a potential role for peripheral venous drainage underlying this difference. Through this study, we were able to illustrate that beyond a mutational context, many factors can downstream regulate gene expression and contribute to different clinicopathological phenotypes. We believe that the combinations of spatial analyses that we used could be inspiring for all researchers wanting to access heterogeneity information of liver tumours.

Focal nodular hyperplasia-like nodules arising in the setting of hepatic vascular disorders with portosystemic shunting show β-catenin activation

Hepatocellular nodules can develop in the setting of chronic hepatic vascular disorders including those characterized by portosystemic shunts such as Abernethy malformation and post-Fontan procedure. The nodules can range from benign lesions such as regenerative nodules, focal nodular hyperplasia (FNH), and hepatocellular adenoma (HCA) to malignant neoplasms such as hepatocellular carcinoma (HCC). In many instances, these nodules are difficult to place into well-defined categories based on radiologic or histologic features. Nodular lesions that resemble FNH are common in this context and have been described as FNH-like nodules, the nature of which is not well-established. This study examines 6 liver resections from patients with vascular disease characterized by portosystemic shunts. A wide range of nodules were present in these cases, including regenerative nodules (n = 2), FNH and FNH-like (n = 30), HCA (n = 10), HCA-like (n = 13), and HCC (n = 2). Six nodules from 3 patients were categorized as FNH-like due to one or more features such as nodular architecture, fibrous septa, and ductular reaction, but lack of typical map-like glutamine synthetase (GS) staining. Further characterization of these 6 FNH-like nodules showed diffuse GS staining in all nodules (3 diffuse homogeneous, 3 diffuse heterogeneous). Targeted next-generation sequencing identified CTNNB1 alterations in all tested FNH-like nodules (n = 4). These results indicate that FNH-like nodules in the setting of chronic hepatic vascular disorders can be neoplastic. Since the presence of β-catenin activation portends a potential risk for malignant progression, GS and β-catenin immunohistochemistry should be obtained in all cases showing FNH-like morphology, with molecular analysis performed in cases with indeterminate staining pattern.

Sonic hedgehog hepatocellular adenoma: magnetic resonance imaging features and correlation with histology

OBJECTIVES

Sonic hedgehog hepatocellular adenoma (shHCA) is a new hepatocellular adenoma (HCA) subgroup characterized by high risk of hemorrhage. ShHCA account for below 10% of all HCA cases and are often associated with female gender, obesity, and non-alcoholic steatohepatitis. No specific MRI characteristics have been described to date. The objective of this study was to assess the value of using MRI to identify shHCA, and correlate MRI findings with histology.

METHODS

We retrospectively collected MRI scans of 29 patients with shHCA from our center and from different liver referral centers to include 35 lesions. Diagnosis of shHCA was assessed by immunohistochemical overexpression of argininosuccinate synthase 1 or prostaglandin D2 synthase, then confirmed by molecular analysis of sonic hedgehog pathway activation and/or by proteomic analysis.

RESULTS

In 46% (n = 16/35) of shHCA cases, we detected intralesional fluid-filled cavities defined on MR images as fluid-like foci markedly hyperintense on T2-weighted sequences, and hypointense on T1-weighted sequences, with or without delayed enhancement. Pathologically, these cavities were observed in 54% of cases as vacuoles filled with blood at different stages of degradation. Hemorrhage and/or necrosis were detected among 71% of cases by MRI analysis (n = 25/35) versus 82% pathologically. Seventeen percent of shHCA cases (n = 6/35) were completely homogeneous via MRI and pathological analysis. No MRI criteria was found in favor of focal nodular hyperplasia, HNF1A-mutated HCA, or typical inflammatory HCA.

CONCLUSION

We reveal the presence of intralesional fluid-filled cavities among 46% of our shHCA cases that represent a new MRI finding possibly helpful for shHCA diagnosis.

CLINICAL RELEVANCE STATEMENT

This multicenter study is the first clinical study about the radiological aspect of this new hepatocellular adenoma subgroup. This highlights a strong correlation between MRI and histological analysis, with a specific pattern emerging for diagnosis.

KEY POINTS

• Sonic hedgehog hepatocellular adenoma is a new hepatocellular adenoma subgroup associated with high risk of hemorrhage, but imaging features of this subgroup remain unknown. • Analysis of MR images and correlation with pathology revealed intralesional fluid-filled cavities and necrotic-hemorrhagic changes. • Intralesional fluid-filled cavities have not yet been described in other adenoma subtypes and represent a new MRI finding for sonic hedgehog hepatocellular adenoma.

[Analysis of MRI features of hepatocyte nuclear factor 1α-inactivated hepatocellular adenoma]

Objective: To investigate the MRI imaging features of hepatocyte nuclear factor 1α- inactivated hepatocellular adenoma (H-HCA). Methods: Clinical data and MRI images of 19 H-HCA cases who were pathologically confirmed at Zhongshan Hospital Affiliated to Fudan University between August 2014 and July 2020 were retrospectively analyzed. Among them, there were 15 females and 4 males, aged 16-47 (32± 7) years old. Tumor number, location, shape, size, boundary, MRI plain scan signal intensity, dynamic enhancement features of each phase, presence or absence of intratumoral fat content, pseudocapsule, and others were analyzed. The differences in apparent diffusion coefficient (ADC) values between the lesion and the surrounding normal liver parenchyma were compared for statistical significance. t-test was used for statistical analysis. Results: There were a total of 24 lesions in 19 cases. 14 cases had solitary lesions, and five cases had multiple lesions. 15 and nine lesions were located in the right and left lobes of the liver, respectively. 20 lesions were round or quasi-round, and four were irregular or lobulated. The tumor's maximal diameter was 0.6-8.6 (3.5 ± 2.4) cm. T(1)-weighted image (WI) showed hyperintense to iso-intense signals in 20 lesions and hypointense signals in four. T(2)WI showed iso-to-slightly high signal intensity in 16 lesions, with two hyperintense and six hypointense signals. Diffusion-weighted image (DWI) revealed hyperintense to iso-intense signals. Lesions mean ADC value was (1.289 ± 0.222)×10(-3) mm(2)/s, while the adjacent normal liver parenchyma's mean ADC value was (1.307 ± 0.236)×10(-3) mm(2)/s, with no statistically significant difference between the two (P > 0.05). During the arterial phase, 15 of the 18 lesions that underwent dynamic contrast-enhanced scanning with gadoxetate disodium (Gd-DTPA) were mildly to moderately enhanced and three were strongly enhanced. The portal and hepatic venous phases had no continuous enhancement, while the delayed phase showed a hypointense signal. During the arterial phase, two of the six lesions scanned by gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid ((Gd-EOB-DTPA) dynamic enhancement were mildly to moderately enhanced, while four were strongly enhanced. The portal and hepatic venous phases had no continuous enhancement, while the transition and hepatobiliary-specific phases showed hypointense signals. Intracellular steatosis occurred in 21 lesions, of which 19 were diffuse steatosis and 16 formed pseudocapsules in the delayed phase. Conclusion: H-HCA often occurs in young females as solitary lesions and has certain MRI features. T1WI anti-phase diffuse signal reduction and post-enhanced hypovascular withdrawal enhancement patterns can aid in accurately diagnosing the disease condition.

Ancillary tests for hepatobiliary neoplasms: what we know and what we need to know

Ancillary tests are commonly used in the surgical pathology setting for diagnosing challenging neoplastic diseases of the liver and biliary tract, while histology and clinical correlation remain to be critically important. With continuous discoveries, more and more useful ancillary tests have become available, which can help distinguish between malignant and benign hepatocellular neoplasms, malignant and benign biliary tract entities, and intrahepatic and metastatic carcinomas. This review will focus on existing and emerging biomarkers (such as glutamine synthetase, organic anion transporting polypeptide 1B3, insulin-like growth factor-II mRNA binding protein-3, S100P, SMAD4, enhancer of zeste homolog 2, albumin, hepatocyte nuclear factor-1β, etc.) that can be used for the diagnosis, classification and prognostication of hepatobiliary neoplasms.

Integrated genotype-phenotype analysis of familial adenomatous polyposis-associated hepatocellular adenomas

Familial adenomatous polyposis (FAP) is an autosomal dominant syndrome caused by a germline mutation in the adenomatous polyposis coli (APC) gene, characterized by numerous colorectal adenomas. In addition, FAP patients may develop extraintestinal manifestations. Several cases of hepatocellular adenomas (HCA) detected accidentally in FAP patients have raised the so-far unsolved question of whether they represent a specific manifestation of FAP or a mere coincidence. To investigate the incidence of liver tumors in FAP patients, we analyzed our diagnostic database from 1991 to 2021. Among the 58 hepatic mass lesions identified, five HCAs occurring in three patients with FAP were identified, and comprehensive morphological, immunohistological, and molecular analysis employing targeted next-generation sequencing was conducted for characterization. The HCAs in this study showed no cytological or histological atypia. They displayed a diffuse, strong positivity for glutamine synthetase but no nuclear beta-catenin immunostaining. In two patients, the adenomas showed moderate immunoreactivity against serum amyloid A. Consistent with the diagnosis of FAP, molecular profiling revealed a pathogenic germline mutation of the APC gene in all analyzed adenomas as well as deleterious somatic second hits. All somatic mutations were localized between codons 1345 and 1577. No mutations were found in the catenin beta 1 gene. HCA in FAP patients can be a specific, although rare, neoplastic manifestation of this inborn disease and represents a distinct subgroup of HCAs. These benign tumors represent an important differential diagnosis for hepatic metastases in FAP patients and require adequate clinical and molecular (diagnostic) assessments for optimal patient guidance.

Hepatic adenoma in a 7-year-old girl: a case report and literature review

BACKGROUND

Hepatocellular adenomas (HCAs) are rare benign tumors of the liver that occur predominantly in women taking oral contraceptives. In children, HCAs comprise < 5% of hepatic tumors. We report a case of HCAs in a 7-year-old girl with estrogen and glucose imbalance.

CASE PRESENTATION

A 7-year-old girl was presented to our hospital with bilateral breast enlargement for 2 months, polydipsia, polyuria, polyphagia, hyperglycemia, and significant weight gain. Computed tomography (CT) showed a 7.2 cm×6.9 cm×5.3 cm round-shaped mass in the left inner lobe of the liver, ovarian ultrasound showed multiple follicles in the ovaries bilaterally, and cranial magnetic resonance imaging (MRI) showed an enlarged superior pituitary. Hematological and biochemical results were as follows: fasting glucose was 19.7 mmol/L, estradiol was 122.9 pmol/L, follicle-stimulating hormone 10.81 IU/L, luteinizing hormone 10.99 IU/L, insulin-like growth factor 1,513 ng/mL, glutamine aminotransferase 86 U/L, and alkaline phosphatase 362 U/L. Thyroid functions, methemoglobin, fetal protein, carcinoembryonic antigen, and chorionic gonadotropin were normal. The patient had a complete surgical resection of the liver tumor, and the postoperative histopathological diagnosis was HCAs. After the surgery, insulin was injected and the glucose levels were stable. During the 36-month follow-up period, neither tumor recurrence nor significant abnormalities were detected using color Doppler ultrasound of the liver. The child's precocious puberty is currently under control.

CONCLUSIONS

HCAs are particularly rare in children with liver tumors, and risk factors for the development of HCAs in children include sex hormone imbalance, obesity, Fanconi anemia (FA), glycogen storage diseases (GSDs) type I, III, and IV, galactosemia, immunodeficiency, congenital portosystemic shunts (CPSS), cardiac hepatopathy status-post Fontan procedure, Hurler syndrome, familial adenomatous polyposis, germline HNF1A mutations, and maturity-onset diabetes of the young type 3. Most HCAs are detected during a physical examination without clinical symptoms, and some patients may present with symptoms such as abdominal pain, abdominal distension, and abdominal masse. Serum liver function tests can show increased alkaline phosphatase (ALP) and γ- glutamyl transferase (GT), whereas α-Fetoprofein (AFP) levels are normal. The definitive diagnosis relies mainly on histopathological examination. Because HCAs can rupture and bleed and become malignant. Early surgical treatment is recommended after detection.

Clinicopathologic characterization of hepatocellular adenomas in men: a multicenter experience

Hepatocellular adenomas (HCAs) are benign liver neoplasms which most commonly present in women in their reproductive age. In men, they are rare and have a higher risk of malignant transformation to hepatocellular carcinoma (HCC). Here we present our multicenter experience with HCA in men in the United States. A total of 27 HCA cases were included, with a mean age of presentation of 37 years (range, 9-69 years) and a mean size of 6.8 cm (range, 0.9-18.5 cm). Based on the 2019 World Health Organization classification, the most common subtype identified was inflammatory HCA (IHCA; 10 cases, 37.0%) followed by unclassified HCA (UHCA; 7 cases, 25.9%), HNF1A-inactivated HCA (H-HCA; 6 cases, 22.2%), β-catenin-activated IHCA (b-IHCA; 3 cases, 11.1%), and β-catenin-activated HCA (b-HCA; 1 case, 3.7%). Six additional cases diagnosed as hepatocellular neoplasm of uncertain malignant potential (HUMP) were also included in the study. These cases presented in a mean age of 46 years (range, 17-64 years) and a size of 10.8 cm (range, 4.2-16.5 cm). We evaluated the significance of androgen receptor (AR) expression by immunohistochemistry (IHC); of the 16 cases with materials available, 8 were considered positive using the Allred score system (2 IHCA, 2 H-HCA, 1 UHCA, and 3 HUMP). Of the total cases, 12 were diagnosed on biopsies, for which follow-up information is available for 7, and none of them show evidence of malignant transformation. Of the 21 resection cases, a concomitant well-differentiated HCC within the same lesion was identified in 5 cases (23.8%), which were diagnosed as HCA (n = 4) or HUMP (n = 1). Overall, 15% of cases in our entire cohort of HCA and HUMP showed concomitant HCC, while none of the 7 biopsy cases showed any malignant transformation on follow-up (range, 22-160 months; mean, 61.8 months).

Influence of progestin-only hormonal use on hepatocellular adenomas: A retrospective cohort study

OBJECTIVES

Exogenous estrogen is associated with growth of hepatocellular adenomas (HCAs), although the influence of progestin-only agents is unknown. We therefore evaluated the association of progestin-only agents on HCA progression compared to no hormone exposure and compared to estrogen exposure in female patients.

STUDY DESIGN

In this single-center, retrospective cohort study of reproductive-aged female patients (ages 16-45) with diagnosed HCAs between 2003 and 2021, we evaluated radiographic HCA growth during discrete periods of well-defined exogenous hormone exposures.

RESULTS

A total of 34 patients were included. Nineteen (55.9%) had follow-up scans during periods without hormone exposure, 7 (20.6%) during estrogen exposure, and 8 (23.5%) during progestin-only exposure. Over a median follow-up of 11 months, percent change in sum of adenoma diameters from baseline to last available scan was -15.0% with progestin-only agents versus 29.4% with estrogen exposure (p = 0.04), and -7.4% with no hormonal exposure (p = 0.52 compared to progestin-only). Greater than 10% growth was observed in two individuals (25.0%) with progestin-only agent use (one patient on high-dose progestin for menorrhagia) versus five individuals (71.4%) with estrogen use (p = 0.13), and 7 (36.8%) with no exogenous hormone use (p = 0.68 vs progestin-only).

CONCLUSIONS

During discrete periods of progestin-only use, HCA growth overall declined, similar to declining growth during periods without exogenous hormonal exposure. This differed from discrete periods of exogenous estrogen exposure, during which time HCAs demonstrated overall increased growth. Though larger studies are needed, these findings support recent guidance supporting progestin-only agents for female patients with HCAs seeking non-estrogen alternatives for contraception.

IMPLICATIONS

In this small retrospective study, we observed overall decrease in HCA size during discrete periods of progestin-only contraception use, similar to that observed during periods without exogenous hormone exposure, supporting their use as a safe alternative to estrogen-containing contraceptives in this patient population.

β-Catenin-activated inflammatory hepatocellular adenoma with pigmentation and atypical features: a case report

Hepatocellular adenomas are rare diseases, defined as benign liver neoplasms composed of cells with hepatocellular differentiation. Differential diagnosis of hepatocellular adenoma from other lesions, including focal nodular hyperplasia and hepatocellular carcinoma, is crucial to determine treatment strategy. We describe a case of β-catenin-activated inflammatory hepatocellular adenoma with malignant transformation. A 50-year-old man with a suspected liver tumor, based on abdominal ultrasonography findings, was referred to our hospital. Contrast-enhanced computed tomography and magnetic resonance imaging revealed a liver tumor in S2 which was enhanced in the arterial phase to the delayed phase. Based on diagnostic imaging findings, hepatocellular adenoma or focal nodular hyperplasia was suspected. We considered the possibility of malignant potential because of the enlargement of the lesion. Thus, we performed a laparoscopic hepatectomy. Histological examination showed pigment deposition in the hepatocytes, which was determined to be lipofuscin. Mild nuclear swelling and atypia in the tumor area indicated nodular growth. Based on the histological and immunohistochemical findings, the diagnosis was ꞵ-catenin-activated inflammatory hepatocellular adenoma with atypical features. The imaging features of hepatocellular adenoma and focal nodular hyperplasia are similar, but if the tumor tends to grow, surgical treatment should be performed because of the possibility of malignant hepatocellular adenoma.

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.

Imaging features of β-catenin-activated hepatocellular adenoma with weak β-catenin activation: A rare case report

We report valuable imaging findings in a case of β-catenin-activated hepatocellular adenoma (β-HCA) with weak β-catenin activation. A 40 year-old female presented with a liver tumor in S8 that was incidentally detected on ultrasonography. The tumor showed marked enhancement and early venous drainage into the middle hepatic vein in the arterial phase of contrast-enhanced computed tomography (CT). The tumor revealed slight hypointensity in the hepatobiliary phase of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI). Six months after detection, the tumor had increased in size and a biopsy indicated hepatocellular carcinoma. The tumor was resected and pathologically diagnosed as β-HCA with weak β-catenin activation such as exon 3 S45 mutation and exon 7/8 mutation. Marked enhancement in the arterial phase of CT and MRI is a characteristic finding of β-HCA with weak β-catenin activation. Furthermore, the degree of β-catenin activation might determine the signal intensity of β-HCA in the hepatobiliary phase of EOB-MRI.

Intraplacental Hepatic Heterotopia

Background: Placental hepatic heterotopia is a benign lesion with unclear histogenesis hypothesized to be of hepatocytic differentiation of yolk sac elements. Of the 14 hepatic heterotopia cases previously reported, 12 cases occurred in preterm labor.Case report: A case of intraplacental hepatic heterotopia in a 27-year-old female with pre-term delivery at 31 + 5 weeks gestational age is described. Histopathological examination revealed a well-demarcated lesion with cohesive, monotonous cells and pale to clear cytoplasm. The differential diagnoses of this lesion included benign, primary and metastatic malignant entities. The lesional cells expressed HepPar-1, CAM 5.2, Glypican-3, and AFP, consistent with cells of hepatic origin.Conclusion: Intraplacental hepatic heterotopia is associated with premature labor. Distinguishing this lesion from maternal and fetal malignancies with similar histopathological presentation has important clinical implications in patient care.

Complications of congenital portosystemic shunts: liver tumors are affected by shunt severity, but pulmonary and neurocognitive associations are not

BACKGROUND AND PURPOSE

Congenital portosystemic shunts (CPSS) are associated with multisystem complications, with the most common being liver tumors. The purpose of this study is to investigate the incidence of complications of CPSS, and to determine the natural history of liver tumors and their relationship with shunt closure.

METHODS

Single-center retrospective cohort study of patients with CPSS referred from 1990 to 2020. Data on demographics, laboratory, radiological and histological investigations, clinical evolution, and surgery were reviewed. Mann-Whitney for continuous data and Fisher's exact test for categorical data were used. A p value of 0.05 was considered significant.

RESULTS

54 patients were investigated for CPSS with a median age of 1.1 years (IQR 0.2-11.8 years) at presentation-7 intrahepatic shunts resolved spontaneously and were excluded. Type 1 (without intrahepatic portal flow) had a higher rate of all hepatic tumors than Type 2 (partial intrahepatic portal flow) [18/22(82%) vs. 9/25(36%); p = 0.003); and malignant tumors (6/22(27%) vs 1/25(4%); (p = 0.04). Following shunt closure, 4/11(36%) of patients experienced partial and 3/11(27%) complete tumor regression. Pulmonary hypertension and hepatopulmonary syndrome affected 4(9%), and 3(6%) patients, respectively. Pulmonary complications affected 1 patient with Type 1 and 6 with Type 2 shunts (p = 0.1). Neurocognitive anomalies were identified in 16/47(34%) patients, 8/22(35%) with Type 1 shunts and 8/25(32%) with Type 2 shunts (p = 0.76). 9/47 (19%) required special needs schooling.

CONCLUSIONS

Severity of portal venous deprivation (Type 1 CPSS) increases the risk of hepatic tumors and surgical closure is associated with a reduction in size or complete resolution of benign tumors.

Differentiation of hepatocellular adenoma by subtype and hepatocellular carcinoma in non-cirrhotic liver by fractal analysis of perfusion MRI

Background

To investigate whether fractal analysis of perfusion differentiates hepatocellular adenoma (HCA) subtypes and hepatocellular carcinoma (HCC) in non-cirrhotic liver by quantifying perfusion chaos using four-dimensional dynamic contrast-enhanced magnetic resonance imaging (4D-DCE-MRI).

Results

A retrospective population of 63 patients (47 female) with histopathologically characterized HCA and HCC in non-cirrhotic livers was investigated. Our population consisted of 13 hepatocyte nuclear factor (HNF)-1α-inactivated (H-HCAs), 7 β-catenin-exon-3-mutated (b^ex3-HCAs), 27 inflammatory HCAs (I-HCAs), and 16 HCCs. Four-dimensional fractal analysis was applied to arterial, portal venous, and delayed phases of 4D-DCE-MRI and was performed in lesions as well as remote liver tissue. Diagnostic accuracy of fractal analysis was compared to qualitative MRI features alone and their combination using multi-class diagnostic accuracy testing including kappa-statistics and area under the receiver operating characteristic curve (AUC). Fractal analysis allowed quantification of perfusion chaos, which was significantly different between lesion subtypes (multi-class AUC = 0.90, p < 0.001), except between I-HCA and HCC. Qualitative MRI features alone did not allow reliable differentiation between HCA subtypes and HCC (κ = 0.35). However, combining qualitative MRI features and fractal analysis reliably predicted the histopathological diagnosis (κ = 0.89) and improved differentiation of high-risk lesions (i.e., HCCs, b^ex3-HCAs) and low-risk lesions (H-HCAs, I-HCAs) from sensitivity and specificity of 43% (95% confidence interval [CI] 23–66%) and 47% (CI 32–64%) for qualitative MRI features to 96% (CI 78–100%) and 68% (CI 51–81%), respectively, when adding fractal analysis.

Conclusions

Combining qualitative MRI features with fractal analysis allows identification of HCA subtypes and HCCs in patients with non-cirrhotic livers and improves differentiation of lesions with high and low risk for malignant transformation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13244-022-01223-6.

Hepatocellular adenoma: Where are we now?

Hepatocellular adenoma (HCA) is a benign hepatocellular neoplasm, commonly occurs in young women with a history of oral contraceptive use. Complications including hemorrhage and malignant transformation necessitate the need for a thorough understanding of the underlying molecular signatures in this entity. Recent molecular studies have significantly expanded our knowledge of HCAs. The well-developed phenotype-genotype classification system improves clinical management through identifying “high risk” subtype of HCAs. In this article, we attempt to provide updated information on clinical, pathologic and molecular features of each subtype of HCAs.

Hepatocellular Adenoma: What We Know, What We Do Not Know, and Why It Matters

In the last 2 decades there has been significant progress in research and diagnosis of hepatocellular adenoma (HCA), resulting in the establishment of a molecular and immunohistological HCA classification. This review aims to fine-tune the current expertise in order to enhance the histopathological diagnostic possibilities, by refining issues that are already known, addressing diagnostic difficulties and identifying still unknown aspects of HCA. We will discuss novel methods to identify HCA subtypes, in particular the sonic hedgehog HCAs and the interpretation of glutamine synthetase patterns for the recognition of beta-catenin mutated HCAs. The major complications of HCAs, bleeding and malignant transformation, will be considered, including the dilemmas of atypical and borderline lesions. Paragraphs on HCAs in different clinical and geographical settings, e.g. pregnancy, cirrhosis and non-western countries are included. The natural history of the different HCA subtypes in relation with age, sex and risk factors is a feature still insufficiently investigated. This is also true for the risks of clinical bleeding and malignant transformation in association with HCA subtypes. As HCA is a relatively rare tumor, a multicenter and multidisciplinary approach across geographical boundaries will be the appropriate method to establish prospective programs to identify, classify and manage HCAs, focusing on several aspects, e.g. etiology, underlying liver disease, complications, regression and growth. Updating what we know, identifying and addressing features that we do not know matters to warrant optimal patient management.

Focal nodular hyperplasia associated with a giant hepatocellular adenoma: A case report and review of literature

BACKGROUND

Focal nodular hyperplasia (FNH) and hepatocellular adenoma (HCA) are well-known benign liver lesions. Surgical treatment is usually chosen for symptomatic patients, lesions more than 5 cm, and uncertainty of diagnosis.

CASE SUMMARY

We described the case of a large liver composite tumor in an asymptomatic 34-year-old female under oral contraceptive for 17-years. The imaging work-out described two components in this liver tumor; measuring 6 cm × 6 cm and 14 cm × 12 cm × 6 cm. The multidisciplinary team suggested surgery for this young woman with an unclear HCA diagnosis. She underwent a laparoscopic left liver lobectomy, with an uneventful postoperative course. Final pathological examination confirmed FNH associated with a large HCA. This manuscript aimed to make a literature review of the current management in this particular situation of large simultaneous benign liver tumors.

CONCLUSION

The simultaneous presence of benign composite liver tumors is rare. This case highlights the management in a multidisciplinary team setting.

Applying criteria for hepatocellular neoplasm of uncertain malignant potential reclassifies more than half of hepatocellular adenomas

OBJECTIVES

Hepatocellular adenoma (HCA) is a benign well-differentiated hepatocellular neoplasm that can be difficult to distinguish from well-differentiated hepatocellular carcinoma (HCC). The term "well-differentiated hepatocellular neoplasm of uncertain malignant potential" (HUMP) has been proposed for neoplasms resembling HCAs, but arising in atypical clinical situations (in females over 50 years old or under 15, in males, with anabolic steroid use, or in some congenital conditions), and/or with atypical pathological features (focal cytological/architectural atypia, β-catenin activation, or focal reticulin loss) insufficient for an unequivocal diagnosis of HCC.

METHODS

This study evaluated HUMP criteria on 42 previously diagnosed HCAs from 33 patients.

RESULTS

Twenty-six (62%) masses from 21 patients were classified as HUMPs. Eleven (42%) had focal cytological atypia, and two (8%) had focal architectural atypia. Four (15%) showed focal reticulin loss. Five (19%) showed evidence of β-catenin activation. Four (12%) HUMP patients were male.

CONCLUSIONS

In this series, HUMP did not correlate with an increased rate of synchronous or metachronous HCC compared to HCA. Clinical colleagues may not accept such a high rate of tumors placed in a category of "uncertain malignant potential". Additional study is warranted to refine criteria for designating well-differentiated hepatocellular neoplasms as of uncertain malignant potential.

Long-term outcomes following resection of hepatocellular adenomas with small foci of malignant transformation or malignant adenomas

BACKGROUND & AIMS

Malignant transformation of hepatocellular adenoma (MT-HCA) may occur in up to 5% of tumours. However, the prognostic value of this event remains poorly described. In this study, we aimed to analyse the long-term outcomes of patients undergoing liver resection (LR) for MT-HCA compared to those of patients resected for hepatocellular carcinoma (HCC) occurring on normal liver parenchyma (NP-HCC).

METHODS

This single-centre retrospective study included all patients who underwent LR for MT-HCA at Beaujon Hospital between 2001 and 2019. MT-HCAs were classified as small foci of malignant transformation HCA (SF-HCA) and as malignant HCA (M-HCA) in cases of predominant HCC foci. Recurrence-free survival (RFS) of MT-HCA was compared with that of NP-HCC after propensity score matching.

RESULTS

Forty patients (24 men, 16 women) underwent LR for MT-HCA, including 23 with SF-HCA and 17 with M-HCA. Of these cases, 16/40 (40%) had β-catenin mutations, 19/40 (47.5%) were inflammatory, 1 was HNF1α-mutated HCA and 4 (10%) were unclassified HCA. Microvascular invasion (12% vs. 0%, p = 0.091) and satellite nodules (25% vs. 4%, p = 0.028) were more frequently observed in M-HCA than in SF-HCA. After a median follow-up of 67 months, 10 (25%) patients with MT-HCA had tumour recurrence, including 9 with M-HCA and 1 with SF-HCA (p = 0.007). M-HCA was linked to significantly poorer 1-, 3-, 5- and 10-year RFS rates than SF-HCA (76%, 63%, 39%, 37% vs. 100%, 100%, 100%, 91%, p = 0.003). Multivariate analysis showed that SF-HCA was independently associated with improved RFS (hazard ratio 0.064; 95% CI 0.008-0.519; p = 0.01). After propensity score matching, NP-HCC was associated with significantly poorer 1-, 3-, 5- and 10-year RFS rates than MT-HCA (p = 0.01).

CONCLUSIONS

HCA with malignant transformation yields a better long-term prognosis than NP-HCC. Among MT-HCA, SF-HCA is associated with a better prognosis than M-HCA.

LAY SUMMARY

The prognostic relevance of malignant transformation of hepatocellular adenoma (HCA) remains unknown. Thus, the aim of our study was to compare the outcomes of patients undergoing liver resection for malignant transformation to those of patients undergoing liver resection for hepatocellular carcinoma (HCC). The main long-term risk after resection for carcinoma is recurrence. In this study, 10/40 patients with malignant transformation of HCA relapsed after resection and we identified age >55 years, presence of satellite nodes, and microvascular invasion as risk factors for long-term recurrence. Compared to patients with HCC, patients who underwent liver resection for HCA with malignant transformation had better long-term survival.

Successful resection of a huge hepatocellular adenoma

Hepatocellular adenoma (HCA) is a rare benign liver tumor that has been reported to occur particularly more often in women who use contraceptives. A 72-year-old woman with no history of using contraceptives presented to our hospital for further examination of a liver tumor. Contrast-enhanced computed tomography and gadoxetic acid-enhanced magnetic resonance imaging revealed a huge solitary hepatic tumor measuring 83 × 76 mm in segments 4, 5, and 8. The differential diagnoses were cholangiocarcinoma and mixed-type hepatocellular carcinoma. Percutaneous needle biopsies were performed twice, and no malignant components were found. Central bi-segmentectomy of the liver was successfully performed. Immunohistochemical staining showed that β-catenin was positive in the membrane of the tumor cells, while fatty acid-binding protein, glutamine synthetase, and amyloid A were negative. These results led to a diagnosis of HCA, hepatocyte nuclear factor-1α-inactivated subtype. The patient's postoperative course was uneventful, and she developed no recurrence for 10 months after surgery. We experienced a rare case of benign HCA. Obtaining a correct preoperative diagnosis is sometimes difficult at the first evaluation. HCA should be considered as a differential diagnosis of liver tumors.

Guidelines for the Treatment of Hepatocellular Adenoma in the Era of Molecular Biology: An Experience-Based Surgeons' Perspective

BACKGROUND

Hepatocellular adenoma (HA) is a rare benign liver tumor with increasing incidence affecting young women. In the last years, much has changed in diagnosis, classification, and treatment, due to the identification of different molecular subtypes. With the evolving knowledge, especially on molecular characteristics of the disease, we are far from a consensus of how to deal with such a multifaceted benign disease METHODS: In the last 20 years, we have treated 134 patients with HA with a mean age of 28 years, being 126 women. Fifty patients had a history of abdominal pain and 13 patients had an acute episode of pain due to rupture and bleeding. Until 2009, adenomas larger than 4 cm in diameter were resected, regardless of gender. From 2010 to 2016, only adenomas larger than 5 cm were referred for surgical treatment. Since 2016, resection was indicated in all female patients with non-steatotic adenomas larger than 5 cm and all adenomas in men.

RESULTS AND DISCUSSION

One hundred twenty-four patients were submitted to resection, being in 21 major resections. Since 2010, 74% of resections were done laparoscopically. Patients with ruptured adenomas were treated with transarterial embolization. Morbidity rate was 8.1% with no mortality. Authors discuss point-by-point all the aspects and presentations of the disease and the best approach. We proposed a therapeutic guideline based on the best available evidence and in our experience.

CONCLUSIONS

Due to the complexity of the disease, the treatment of HA is one the best examples of an individualized approach.

18F-FDG PET/CT of hepatocellular adenoma subtypes and review of literature

INTRODUCTION

This study evaluates 18F-FDG PET/CT imaging characteristics of pathologically proven hepatocellular adenoma (HCA) subtypes.

METHODS

This is a retrospective review of an institutional database (2011-2017) for subjects with a pathologic diagnosis of hepatic adenomas established within 6 months of a pre-treatment 18F-FDG PET/CT exam. An expert pathological review by a hepatopathologist was performed to confirm diagnosis and subtype HCA. A review of the 18F-FDG PET/CT exams was performed by two board-certified nuclear radiologists in consensus. Corresponding demographic and clinical data were obtained by electronic chart review.

RESULTS

Nine subjects were identified. An HCA subtype was established in seven subjects (4 HNF1A-mutated and 3 Inflammatory). The mean HCA lesion size was 2.8 cm (range 0.6-6.2, SD 2.0) with a mean SUVmax of 5.9 (range 2.1-18.9, SD 5.1). The SUV values of HNF1A-mutated HCA were significantly higher than inflammatory HCA: lesion SUVmax (5.3 ± 1.48 vs. 2.8 ± 0.59, p < 0.033), lesion-to-liver SUVmax ratio (1.4 ± 0.22 vs. 0.8 ± 0.21, p = 0.031), lesion SUVmean (3.6 ± 0.37 vs. 2.0 ± 0.46, p = 0.0086).

CONCLUSION

HNF1A-mutated HCA may have greater SUV values than inflammatory HCA on 18F-FDG PET/CT exams. However, there are contradictory data in the literature and further investigation is warranted.

CT-Based Radiomics Nomogram: A Potential Tool for Differentiating Hepatocellular Adenoma From Hepatocellular Carcinoma in the Noncirrhotic Liver

RATIONALE AND OBJECTIVES

To evaluate the value of a radiomics nomogram for preoperative differentiating hepatocellular adenoma (HCA) from hepatocellular carcinoma (HCC) in the noncirrhotic liver.

MATERIALS AND METHODS

One hundred and thirty-one patients with HCA (n = 46) and HCC (n = 85) were divided into a training set (n = 93) and a test set (n = 38). Clinical data and CT findings were analyzed. Radiomics features were extracted from the triphasic contrast CT images. A radiomics signature was constructed with the least absolute shrinkage and selection operator algorithm and a radiomics score was calculated. Combined with the radiomics score and independent clinical factors, a radiomics nomogram was developed by multivariate logistic regression analysis. The performance of the radiomics nomogram was assessed by calibration, discrimination and clinical usefulness.

RESULTS

Gender, age, and enhancement pattern were the independent clinical factors. Three thousand seven hundred and sixty-eight features were extracted and reduced to 7 features as the optimal discriminators to build the radiomics signature. The radiomics nomogram (area under the curve [AUC], 0.96; 95% confidence interval [CI], 0.93-0.99) and the clinical factors model (AUC, 0.93; 95%CI, 0.88-0.99) showed better discrimination capability (p = 0.001 and 0.047) than the radiomics signature (AUC, 0.83; 95%CI, 0.74-0.92) in the training set. In the test set, the radiomics nomogram (AUC, 0.94; 95%CI, 0.87-1.00) performed better (p = 0.013) than the radiomics signature (AUC, 0.75; 95%CI, 0.59-0.91). Decision curve analysis showed the radiomics nomogram outperformed the clinical factors model and the radiomics signature in terms of clinical usefulness.

CONCLUSION

The CT-based radiomics nomogram has the potential to accurately differentiate HCA from HCC in the noncirrhotic liver.

Hepatocellular adenoma initially diagnosed as hepatocellular carcinoma with resistance to proton beam radiotherapy - A case report

Introduction and importance

Hepatocellular adenoma (HCA) is a rare liver tumor. We report a case of a radio-resistant liver tumor that was removed surgically and found to be HCA.

Case presentation

A 37-year-old Japanese man was incidentally diagnosed with a liver tumor. He had no history of viral hepatitis nor metabolic disorders. MRI revealed a tumor enhancing in arterial phase, followed by washout in late phase, and hypointensity in hepatobiliary phase. A diagnosis of hepatocellular carcinoma (HCC) was made and surgery was advised. However, the patient chose proton beam radiotherapy. Although the tumor initially shrunk, it increased in size thereafter. Therefore, anterior sectionectomy was performed. Histology revealed proliferation of hepatocytes without cytologic atypia. On immunohistochemistry, CRP, SAA, GS, L-FABP, and nuclear expression of β-catenin were positive. A final diagnosis of mixed inflammatory and β-catenin activated HCA was made.

Clinical discussion

HCA is associated with obesity. The present case was a slightly obese man without history of viral hepatitis. In such cases, HCA should be considered. In the present case, proton beam radiotherapy was performed for a diagnosis of HCC. However, the tumor was radio-resistant.

Conclusion

HCA shows an almost equal male to female ratio in the Asian population. Molecular classification is vital in the management of HCA. HCC and HCA are often difficult to differentiate; tumor biopsy is necessary for patients with atypical imaging findings and in younger patients without underlying liver disease. Since the effectiveness of radiation therapy on HCA has not been reported, surgery should be preferred.

•

HCA is more prevalent in women in the western countries, while equal gender distribution in Asian countries

•

Subgroups show different imaging findings. I-HCA, atoll sign; b-HCA, iso-hyperintensity in the hepatobiliary phase

•

In the present case, the tumor showed resistance to radiation

Hepatocellular adenomas: recent updates

Hepatocellular adenoma (HCA) is a heterogeneous entity, from both the histomorphological and molecular aspects, and the resultant subclassification has brought a strong translational impact for both pathologists and clinicians. In this review, we provide an overview of the recent updates on HCA from the pathologists’ perspective and discuss several practical issues and pitfalls that may be useful for diagnostic practice.

Long-term complete remission of large hepatocellular adenoma after bariatric surgery

We report the case of an obese woman with a large hepatocellular adenoma (HCA) of 8.0 cm in diameter, followed for 5 years after Roux-en-Y Gastric Bypass, with a complete radiologic remission of the liver mass. Four other cases have been published with HCA regression after bariatric surgery, but none with long-term follow-up. As the association between obesity and HCA has been increasingly described, bariatric surgery should be considered a therapeutic option for stage 2 obese patients.

Beta-catenin-activated hepatocellular adenoma in a male

Beta-catenin-activated hepatocellular adenoma is potentially malignant and warrants careful follow-up and surgical resection. Here, we report a 48-year-old man in whom a 55 mm single liver tumor was incidentally detected in the S1 segment. Contrast-enhanced computed tomography scans showed no enhancement in the early phase and a slight defection in the late phase. The tumor was enhanced hyperintensity in the hepatobiliary phase on Gd-ethoxybenzyl-diethylenetriaminepentaacetic acid-enhanced magnetic resonance imaging. The histologic features of ultrasound-guided fine-needle aspiration biopsy indicated hepatocellular adenoma, and the tumor was immunohistochemically positive for glutamine synthetase and β-catenin. Considering the risk of malignant transformation, he underwent laparoscopic-assisted partial liver resection. The resected tumor did not contain any malignant lesions. This case indicates that aspiration needle biopsy and immunohistochemistry were useful for histological diagnosis and treatment decisions based on the molecular definition of hepatocellular adenoma.

Hepatocellular Carcinoma Arising from Hepatocellular Adenoma in an Elderly Male Patient

Hepatocellular adenoma is a benign tumor of the liver occurring predominantly in young women taking oral contraceptives. The malignant transformation of hepatocellular adenoma into hepatocellular carcinoma has rarely been reported. Herein, we report the case of an elderly male patient with hepatocellular carcinoma that developed from hepatocellular adenoma. The patient's high risk for surgery and conflicting biopsy and imaging results made it difficult to determine the treatment direction. Eventually, the mass was completely removed by laparoscopic left hemi-hepatectomy without complications.

HBP-enhancing hepatocellular adenomas and how to discriminate them from FNH in Gd-EOB MRI

BACKGROUND

Recent studies provide evidence that hepatocellular  adenomas  (HCAs) frequently take up gadoxetic acid (Gd-EOB) during the hepatobiliary phase (HBP). The purpose of our study was to investigate how to differentiate between Gd-EOB-enhancing HCAs and focal nodular hyperplasias (FNHs). We therefore retrospectively included 40 HCAs classified as HBP Gd-EOB-enhancing lesions from a sample of 100 histopathologically proven HCAs in 65 patients. These enhancing HCAs were matched retrospectively with 28 FNH lesions (standard of reference: surgical resection). Two readers (experienced abdominal radiologists blinded to clinical data) reviewed the images evaluating morphologic features and subjectively scoring Gd-EOB uptake (25-50%, 50-75% and 75-100%) for each lesion. Quantitative lesion-to-liver enhancement was measured in arterial, portal venous (PV), transitional and HBP. Additionally, multivariate regression analyses were performed.

RESULTS

Subjective scoring of intralesional Gd-EOB uptake showed the highest discriminatory accuracies (AUC: 0.848 (R#1); 0.920 (R#2)-p < 0.001) with significantly higher uptake scores assigned to FNHs (Cut-off: 75%-100%). Typical lobulation and presence of a central scar in FNH achieved an accuracy of 0.750 or higher in at least one reader (lobulation-AUC: 0.809 (R#1); 0.736 (R#2); central scar-AUC: 0.595 (R#1); 0.784 (R#2)). The multivariate regression emphasized the discriminatory power of the Gd-EOB scoring (p = 0.001/OR:22.15 (R#1) and p < 0.001/OR:99.12 (R#2). The lesion-to-liver ratio differed significantly between FNH and HCA in the PV phase and HBP (PV: 132.9 (FNH) and 110.2 (HCA), p = 0.048 and HBP: 110.3 (FNH) and 39.2 (HCA), p < 0.001)), while the difference was not significant in arterial and transitional contrast phases (p > 0.05).

CONCLUSION

Even in HBP-enhancing HCA, characterization of Gd-EOB uptake was found to provide the strongest discriminatory power in differentiating HCA from FNH. Furthermore, a lobulated appearance and a central scar are more frequently seen in FNH than in HCA.

Unclassified hepatocellular adenoma with beta-catenin mutation: a case report

Background

Hepatocellular adenoma (HCA) subtypes are considered as risk factors for malignant transformation; thus, an accurate diagnosis is important. We report a case of resected HCA previously diagnosed as unclassified HCA using immunohistochemistry, subsequently discovered to harbor a mutation in exon 3 of the beta (β)-catenin gene using deoxyribonucleic acid (DNA) sequencing.

Case presentation

The patient was a 26-year-old woman who was referred to our hospital because of a 150-mm tumor in the right lobe of the liver. Considering the possibility of malignancy, we performed right lobe hepatectomy. Based on the histopathological and immunohistochemical findings, the tumor was diagnosed as an unclassified HCA. Next, we performed sequencing of DNA isolated from the tumor and identified a mutation in exon 3 of β-catenin, suggesting that the tumor contained an activating mutation of the β-catenin gene.

Conclusion

β-Catenin mutations in HCA cannot be detected by immunohistochemistry alone, and molecular analysis is required to accurately diagnose and evaluate its prognosis.

"Bull’s eye” appearance of hepatocellular adenomas in patients with glycogen storage disease type I — atypical magnetic resonance imaging findings: Two case reports

BACKGROUND

Hepatocellular adenomas are rare tumors that can occur in patients with glycogen storage disease type I.

CASE SUMMARY

We herein report two cases of histologically proven hepatocellular adenomas in patients with glycogen storage disease type I. Magnetic resonance imaging (MRI) was performed after bolus injection of gadoxetate disodium, a liver-specific gadolinium-based MRI contrast agent. In the present cases, some of the hepatocellular adenomas showed unexpectedly a “bull’s eye” appearance on T2-weighted and post-contrast images, which was not previously described as imaging findings of hepatocellular adenomas in glycogen storage disease. A bull’s eye appearance on T2-weighted images can be encountered in both benign (i.e., abscess) or malignant (i.e., epithelioid hemangioendothelioma, cholangio-carcinoma, and metastases) hepatic lesions.

CONCLUSION

We present two cases of hepatocellular adenomas in patients with glycogen storage disease type 1, in which gadoxetate disodium-MRI showed atypical imaging findings for hepatocellular adenomas. At present there is no systematic study evaluating MRI findings of hepatocellular adenomas in patients with glycogen storage disease, further studies are needed to specifically investigate this issue.

Giant pedunculated hepatocellular adenoma masquerading as a subdiaphragmatic mass: Diagnostic challenges of a rare tumor

Giant pedunculated hepatocellular adenomas are extremely rare tumors and often detected incidentally on cross-sectional imaging studies. We report the case of a 34-year-old woman who underwent cross-sectional imaging for staging evaluation of a uterine tumor. A large left subdiaphragmatic mass, without clear connection to the liver, was seen prompting diagnostic laparoscopy; during which a large pedunculated mass attached to the left lobe of the liver was found and resected. This case report highlights the challenges and pitfalls in the imaging diagnosis of pedunculated hepatocellular adenomas, such as difficulty in characterizing the mass or inability to identify the vascular attachment to the liver. Image-guided biopsy and diagnostic laparoscopy are valuable tools to establish diagnosis; most of these lesions are amenable to laparoscopic resection.

Hepatocellular adenomas: review of pathological and molecular features

Hepatocellular adenoma (HCA) is a rare benign liver neoplasm which predominantly occurs in women in the reproductive age group taking oral contraception. Since 2002, the terminology HCA has defined an heterogeneous group of neoplastic benign hepatocellular proliferations composed of different subtypes. The genotype-phenotype classification led to the description of 5 well-recognized subtypes based on morphological and immunophenotypical features, that are currently used in practice: HNF1A inactivated HCA, inflammatory HCA, β-catenin mutated HCA, sonic hedgehog HCA, and unclassified HCA. The main complications observed in HCAs are bleeding and malignant transformation. Risk of malignant transformation into hepatocellular carcinoma (HCC), more frequent in men, is also dependent to tumor size and HCA subtype, reaching 40% in β-catenin mutated HCA. The distinction of HCA from well-differentiated HCC remains difficult in some cases, leading to the diagnosis of so-called "atypical/borderline HCA". The management of HCA is now based on multidisciplinary approach including clinicians, radiologists, and pathologists integrating gender, tumor size, and HCA subtyping.

Hepatospecific MR contrast agent uptake on hepatobiliary phase can be used as a biomarker of marked β-catenin activation in hepatocellular adenoma

OBJECTIVES

To assess the value of hepatospecific MR contrast agent uptake on hepatobiliary phase (HBP) images to detect marked activation of the β-catenin pathway in hepatocellular adenomas (HCAs).

METHODS

This multicentric retrospective IRB-approved study included all patients with a pathologically proven HCA who underwent gadobenate dimeglumine-enhanced liver MRI with HBP. Tumor signal intensity on HBP was first assessed visually, and lesions were classified into three distinct groups-hypointense, isointense, or hyperintense-according to the relative signal intensity to liver. Uptake was then quantified using the lesion-to-liver contrast enhancement ratio (LLCER). Finally, the accuracy of HBP analysis in depicting marked β-catenin activation in HCA was evaluated.

RESULTS

A total of 124 HCAs were analyzed including 12 with marked β-catenin activation (HCA B+). Visual analysis classified 94/124 (76%), 12/124 (10%), and 18/124 (14%) HCAs as being hypointense, isointense, and hyperintense on HBP, respectively. Of these, 1/94 (1%), 3/12 (25%), and 8/18 (44%) were HCA B+, respectively (p < 0.001). The LLCER of HCA B+ was higher than that of HCA without marked β-catenin activation in the entire cohort (means 4.9 ± 11.8% vs. - 19.8 ± 11.4%, respectively, p < 0.001). A positive LLCER, i.e., LLCER ≥ 0%, had 75% (95% CI 43-95%) sensitivity and 97% (95% CI 92-99%) specificity, with a LR+ of 28 (95% CI 8.8-89.6) for the diagnosis of HCA B+.

CONCLUSIONS

Hepatospecific contrast uptake on hepatobiliary phase is strongly associated with marked activation of the β-catenin pathway in hepatocellular adenoma, and its use might improve hepatocellular adenoma subtyping on MRI.

KEY POINTS

• Tumor uptake on hepatobiliary phase in both the visual and quantitative analyses had a specificity higher than 90% for the detection of marked β-catenin activation in hepatocellular adenoma. • However, the sensitivity of visual analysis alone is inferior to that of LLCER quantification on HBP due to the high number of HCAs with signal hyperintensity on HBP, especially those developed on underlying liver steatosis.

Focal lesions of the liver: imaging appearances and management

With the increasing use of cross-sectional imaging, the detection of incidental liver lesions has become more common. Accurate and reliable characterisation of these is vital for optimal patient care. Owing to the great improvements in medical imaging technology in recent years, particularly magnetic resonance imaging, it is now possible to characterise a significant proportion of these non-invasively. This is of paramount importance in improving patient safety and reducing costs by avoiding unnecessary biopsies. This article gives a synopsis of the different imaging modalities for liver. It depicts the salient imaging features of the common benign and malignant focal liver lesions on different imaging modalities, with emphasis on magnetic resonance imaging. It demonstrates the pseudolesions, variants, mimics and pitfalls that occur in liver imaging. The tailored magnetic resonance imaging protocols including abbreviated ones, the contrast agents and the pathway for managing incidental liver lesions in the author's institution are covered.

Circulating exosomal microRNAs as potential biomarkers of hepatic injury and inflammation in a murine model of glycogen storage disease type 1a

Most patients affected by glycogen storage disease type 1a (GSD1a), an inherited metabolic disorder caused by mutations in the enzyme glucose-6-phosphatase-α (G6Pase-α), develop renal and liver complications, including the development of hepatocellular adenoma/carcinoma. The purpose of this study was to identify potential biomarkers of the pathophysiology of the GSD1a-affected liver. To this end, we used the plasma exosomes of a murine model of GSD1a, the LS-G6pc ^{-/ -} mouse, to uncover the modulation in microRNA expression associated with the disease. The microRNAs differentially expressed between LS-G6pc ^-/- and wild-type mice, LS-G6pc ^-/- mice with hepatocellular adenoma and LS-G6pc ^-/- mice without adenoma, and LS-G6pc ^-/- mice with amyloidosis and LS-G6pc ^-/- mice without amyloidosis were identified. Pathway analysis demonstrated that the target genes of the differentially expressed microRNA were significantly enriched for the insulin signaling pathway, glucose and lipid metabolism, Wnt/β-catenin, telomere maintenance and hepatocellular carcinoma, and chemokine and immune regulation signaling pathways. Although some microRNAs were common to the different pathologic conditions, others were unique to the cancerous or inflammatory status of the animals. Therefore, the altered expression of several microRNAs is correlated with various pathologic liver states and might help to distinguish them during the progression of the disease and the development of late GSD1a-associated complications.

Malignant Transformation of an HNF1a-Inactivated Hepatocellular Adenoma to Hepatocellular Carcinoma

Hepatocellular adenomas (HCA) are rare benign tumors of the liver, occurring predominantly in females using oral contraceptives. Our case describes a 66-year-old woman presenting with a palpable mass in her upper abdomen. Contrast-enhanced computed tomography and magnetic resonance imaging showed a large exophytic mass protruding from the caudal border of liver segments IV and V, without visible metastases. Laparoscopic resection of the tumor and gallbladder was performed. Histopathological examination showed a hepatocellular carcinoma with areas of HNF1a-HCA (H-HCA). This case shows that malignant transformation is possible in H-HCA. We present our preoperative decision-making process, as well as the role of imaging techniques in this rare case.

Should bariatric surgery be offered for hepatocellular adenomas in obese patients?

BACKGROUND

Obesity and metabolic syndrome are increasingly recognized as risk factors for development of hepatocellular adenoma (HCA). The implications of weight loss on HCA regression has not been previously reviewed.

OBJECTIVES

To analyze the effects of surgical and nonsurgical weight loss on HCA.

SETTING

University Tertiary Hospital.

METHODS

Literature review of full-text articles from PubMed and Scopus on patients with HCA who underwent surgical or nonsurgical weight loss was performed. Only English language articles were included and editorial comments were excluded. Wilcoxon signed rank test was used for paired data analysis. Spearman correlation was used for correlation between percent excess weight loss (%EWL) and number and size of HCA lesions.

RESULTS

Out of 4 studies, 7 patients were included in this review, all of whom were female. The median preintervention body mass index was 41 kg/m² compared with the postintervention body mass index of 28 kg/m² (P = .002). The %EWL following intervention positively correlated to reduction in number of HCA lesions (%) postintervention, with a Spearman correlation of .78 (P = .04). Similarly, %EWL postintervention was positively correlated, though not statistically significant, to reduction in lesion size (%), with a Spearman correlation of .46 (P = .29). All patients who were candidates for liver resection preintervention based on lesion size > 5 cm avoided liver resection postintervention following surgical and nonsurgical weight loss.

CONCLUSIONS

Effective long-term weight loss by surgical and nonsurgical methods result in regression of HCAs. Weight loss could avoid major liver resections or decrease the morbidity associated with liver surgery. Bariatric surgery should be considered as an option for management of surgically challenging HCAs in carefully selected obese patients. Multicenter long-term trials, while adjusting for cofounding factors, are required to determine the effects of surgical compared with nonsurgical weight loss on maintenance of HCA regression.

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.

Hepatocellular adenoma in the paediatric population: Molecular classification and clinical associations

Hepatocellular adenomas (HCAs) represent rare, benign liver tumours occurring predominantly in females taking oral contraceptives. In children, HCAs comprise less than 5% of hepatic tumours and demonstrate association with various conditions. The contemporary classification of HCAs, based on their distinctive genotypes and clinical phenotypes, includes hepatocyte nuclear factor 1 homeobox alpha-inactivated HCAs, beta-catenin-mutated HCAs, inflammatory HCAs, combined beta-catenin-mutated and inflammatory HCAs, sonic hedgehog-activated HCAs, and unclassified HCAs. In children, there is a lack of literature on the characteristics and distribution of HCA subtypes. In this review, we summarized different HCA subtypes and the clinicopathologic spectrum of HCAs in the paediatric population.

Unclassified hepatocellular adenoma with histological brown pigment deposition and serum PIVKA-II level elevation: a case report

Background

Hepatocellular adenoma (HCA) is conventionally considered a rare benign liver tumor, but advanced studies have revealed that HCA is heterogeneous, and may include a type that is prone to malignant transformations. Differentiation between well-differentiated hepatocellular carcinoma and focal nodular hyperplasia is necessary to diagnose hepatocellular adenoma through imaging; however, the tumor marker of hepatocellular carcinoma, protein induced by vitamin K absence, or antagonist II (PIVKA-II), is rarely positive in hepatocellular adenoma.

Case presentation

A 44-year-old woman presented to our hospital with complaints of loss of appetite and weight loss. Multidetector row computed tomography revealed a liver tumor (diameter, 80 mm) that was enhanced in the arterial phase. Her serum PIVKA-II level was very high (3327 mAU/mL). Based on the enlargement of the mass and the results of the diagnostic imaging, hepatocellular adenoma or hepatocellular carcinoma was suspected, and we considered the possibility of a malignant transformation due to the high level of serum PIVKA-II; thus, we performed hepatectomy. Histological examination showed brown pigment deposition in the hepatocytes, which was determined to be lipofuscin granules. Based on immunohistochemical findings, the diagnosis was unclassified hepatocellular adenoma. Immunohistochemical examinations revealed that the adenoma cells in the tumor were positive for PIVKA-II. Her serum PIVKA-II level returned to normal after the resection.

Conclusions

We present a case of unclassified hepatocellular adenoma with brown pigment deposition and elevation of serum PIVKA-II level. For the differentiation of liver tumors with high levels of PIVKA-II and hypervascular mass, hepatocellular adenoma should be considered.