Focal Fatty Change Research Articles

WFUMB Review Paper. Incidental Findings in Otherwise Healthy Subjects, How to Manage: Liver.

An incidental focal liver lesion (IFLL) is defined as a hepatic lesion identified in a patient imaged for an unrelated reason. They are frequently encountered in daily practice, sometimes leading to unnecessary, invasive and potentially harmful follow-up investigations. The clinical presentation and the imaging aspects play an important role in deciding if, and what further evaluation, is needed. In low-risk patients (i.e., without a history of malignant or chronic liver disease or related symptoms), especially in those younger than 40 years old, more than 95% of IFLLs are likely benign. Shear Wave liver Elastography (SWE) of the surrounding liver parenchyma should be considered to exclude liver cirrhosis and for further risk stratification. If an IFLL in a low-risk patient has a typical appearance on B-mode ultrasound of a benign lesion (e.g., simple cyst, calcification, focal fatty change, typical hemangioma), no further imaging is needed. Contrast-Enhanced Ultrasound (CEUS) should be considered as the first-line contrast imaging modality to differentiate benign from malignant IFLLs, since it has a similar accuracy to contrast-enhanced (CE)-MRI. On CEUS, hypoenhancement of a lesion in the late vascular phase is characteristic for malignancy. CE-CT should be avoided for characterizing probable benign FLL and reserved for staging once a lesion is proven malignant. In high-risk patients (i.e., with chronic liver disease or an oncological history), each IFLL should initially be considered as potentially malignant, and every effort should be made to confirm or exclude malignancy. US-guided biopsy should be considered in those with unresectable malignant lesions, particularly if the diagnosis remains unclear, or when a specific tissue diagnosis is needed.

Morphological, dynamic and functional characteristics of liver pseudolesions and benign lesions.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide and one of the most common causes of death among patients with cirrhosis, developing in 1-8% of them every year, regardless of their cirrhotic stage. The radiological features of HCC are almost always sufficient for reaching the diagnosis; thus, histological confirmation is rarely needed. However, the study of cirrhotic livers remains a challenge for radiologists due to the developing of fibrous and regenerative tissue that cause the distortion of normal liver parenchyma, changing the typical appearances of benign lesions and pseudolesions, which therefore may be misinterpreted as malignancies. In addition, a correct distinction between pseudolesions and malignancy is crucial to allow appropriate targeted therapy and avoid treatment delays.The present review encompasses technical pitfalls and describes focal benign lesions and pseudolesions that may be misinterpreted as HCC in cirrhotic livers, providing the imaging features of regenerative nodules, large regenerative nodules, siderotic nodules, hepatic hemangiomas (including rapidly filling and sclerosed hemangiomas), segmental hyperplasia, arterioportal shunts, focal confluent fibrosis and focal fatty changes. Lastly, the present review explores the most promising new imaging techniques that are emerging and that could help radiologists differentiate benign lesions and pseudolesions from overt HCC.

Preclinical safety profile of a liver-localized mitochondrial uncoupler: OPC-163493.

Mitochondrial uncouplers (mUncouplers) are known to exhibit a variety of toxic effects in animals. Here we report a safety profile of an mUncoupler, OPC-163493, recently synthesized at Otsuka Pharmaceutical Co, Ltd, and its development as a therapeutic agent for treating diabetes. To understand the acute and subchronic toxicity of OPC-163493, single and repeated oral dose studies in rats, dogs, and monkeys were performed. In the rat studies, rigor mortis and increased body temperatures were observed in the high dose group. Focal necrosis, fatty change, and granular eosinophilic cytoplasm of the hepatocytes were also observed in the high dose group. In the dog studies, gastrointestinal manifestations were observed with decreased body weight and decreased food consumption in the high dose group. Necrotizing arteritis was observed in multiple organs as well as meningitis with hemorrhage in the brain. In the monkey studies, vomiting, decreased food consumption, and decreased locomotor activity were observed in the high dose group. Degeneration of the proximal convoluted tubules and the straight tubular epithelium, regeneration of the proximal tubular epithelium, and degeneration of the collecting tubular epithelium were observed. The target organs of OPC-163493 were liver, blood vessels, and kidney in rats, dogs, and monkeys, respectively. In rats, dogs, and monkeys, safety ratios were 100:1, 13:1, and 20:1, respectively, in terms of total exposure (AUC24h). These safety ratios showed clear separation between exposure to OPC-163493 in animals at NOAEL and the exposure at the effective dose in ZDF rats. This information should contribute to the drug development of new and effective mUncoupler candidates.

Introducing “K-shaped sign”, a new finding on CT to detect a pancreatic cancer at the early state

Introduction: We found and evaluated a specific change of the pancreas on CT just before a pancreatic cancer appears. Methods: We selected 32 patients among 241 patients with advanced pancreatic cancer. All 32 patients took abdominal CT more than one time, before their pancreatic cancers were diagnosed. Eight of the 32 patients underwent pancreatic resection.We reviewed all patients' abdominal CT and checked how abnormal findings appeared in the pancreas before finding their pancreatic cancer. Results: Twenty-three (71.8%) of the 32 patients had a localized constriction of the pancreatic parenchyma before appearing the pancreatic cancer. We named it “K-shaped sign” based on the figure. All of the 23 patients showed focal fatty changes around the area the K-shaped sign appeared. Four (17.3%) of the 23 patients had both K-shape sign and a partial main pancreatic duct dilatation. Nineteen of the 32 patients had a normal pancreas without focal fatty change on CT before the K-shaped sign occurred. Thirteen of the 32 patients had detected the K-shaped sign since the initial abdominal CT. All the 32 patients had the pancreatic cancer in the K-shaped sign's area. Conclusion: We introduced new CT finding before pancreatic cancer could be found, and named it “K-shaped sign” on CT. Although the “K-shaped sign” phenomenon has to be associated with early pancreatic cancer, it is unclear what the cause of the phenomenon is. When the K-shaped sign is observed on CT, the onset of a pancreatic cancer should be considered and determined by using more precise modalities.

Liver Focal Fatty Change Evaluated by Contrast-Enhanced Ultrasound: A Retrospective Study in an Ultrasound Expert Center

The goal of this paper was to evaluate the liver focal fatty change (either fat infiltration or fatty sparing) assessed by contrast-enhanced ultrasound (CEUS), in a tertiary center. A retrospective study was performed that evaluated a cohort of 2904 de novo focal liver lesions (FLLs) assessed by CEUS (according to EFSUMB guidelines) over a period of seven years (2010-2016). Focal fatty change (FFC) lesions that were referred for contrast assessment were 319/2904 (11%). From 2904 FLLs, 979 (33.7%) were also evaluated by a second line imaging technique or histology (due to the incomplete EFSUMB diagnostic pattern criteria). We evaluated the sensitivity, specificity and accuracy of CEUS for the FFC that were confirmed by a second line imaging technique (CT, MRI) or histology. For the statistical analysis we used OpenEpi software. From 2904 de novo FLLs, 319 (11%) were FFC, in female 46.4%, in male 53,6%; mean age 54.3+/- 11.9 years, mean lesion size: 3.37±2.13 cm. 233/319 (73%)- were fatty sparing and 86/319 (27%)-fat infiltration. FFC represented by focal infiltration were diagnosed on liver with chronic hepathopaty: 25/319 (7.8%) and 61/319 (92.8%) on liver without fibrosis. CEUS was conclusive (lesions with typical enhancement pattern as presented in EFSUMB guidelines) for the diagnosis of FFC in 97.2% of cases. From 979 FLLs group (CT, MRI or histology for the final diagnosis), 31/979 (3.2%) were FFC. 22/31 (71%) were fatty sparing and 9/31 (29%) were fat infiltration. CEUS performance in the diagnosis of FFC was: 72.73% Sensitivity; 99.67% Specificity; 98.28% Accuracy. The performance of CEUS was influenced by the diameter of the lesion (>5cm) and the presence of sever fibrosis ≥F3. CEUS is an accurate and specific method for the diagnosis of focal fatty changes; still the results can be influenced by the size of the lesion and the presence of liver cirrhosis.

Imaging patterns and focal lesions in fatty liver: a pictorial review.

Non-alcoholic fatty liver disease is the most common cause of chronic liver disease and affects nearly one-third of US population. With the increasing trend of obesity in the population, associated fatty change in the liver will be a common feature observed in imaging studies. Fatty liver causes changes in liver parenchyma appearance on imaging modalities including ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) and may affect the imaging characteristics of focal liver lesions (FLLs). The imaging characteristics of FLLs were classically described in a non-fatty liver. In addition, focal fatty change and focal fat sparing may also simulate FLLs. Knowledge of characteristic patterns of fatty change in the liver (diffuse, geographical, focal, subcapsular, and perivascular) and their impact on the detection and characterization of FLL is therefore important. In general, fatty change may improve detection of FLLs on MRI using fat suppression sequences, but may reduce sensitivity on a single-phase (portal venous) CT and conventional ultrasound. In patients with fatty liver, MRI is generally superior to ultrasound and CT for detection and characterization of FLL. In this pictorial essay, we describe the imaging patterns of fatty change in the liver and its effect on detection and characterization of FLLs on ultrasound, CT, MRI, and PET.

Focal fatty change of the liver mimicking hepatocellular carcinoma: Reports of three cases and literature review

Focal fatty change of the liver mimicking hepatocellular carcinoma: Reports of three cases and literature review

Prediction of microvascular invasion of hepatocellular carcinomas with gadoxetic acid-enhanced MR imaging: Impact of intra-tumoral fat detected on chemical-shift images

PurposeTo investigate the impact of intra-tumoral fat detected by chemical-shift MR imaging in predicting the MVI of HCC. Materials and methodsGadoxetic acid-enhanced MR imaging of 365 surgically proven HCCs from 365 patients (306 men, 59 women; mean age, 55.6 years) were evaluated. HCCs were classified into two groups, fat-containing and non-fat-containing, based on the presence of fat on chemical-shift images. Fat-containing HCCs were subdivided into diffuse or focal fatty change groups. Logistic regression analyses were used to identify clinical and MR findings associated with MVI. ResultsBased on MR imaging, 66 tumors were classified as fat-containing HCCs and 299 as non-fat-containing HCCs. Among the 66 fat-containing HCCs, 38 (57.6%) showed diffuse fatty changes and 28 (42.4%) showed focal fatty changes. MVI was present in 18 (27.3%) fat-containing HCCs and in 117 (39.1%) non-fat-containing HCCs (P=0.07). Univariate analysis revealed that serum alpha-fetoprotein (AFP) and tumor size were significantly associated with MVI (P<0.001). A multiple logistic regression analysis showed that log AFP (odds ratio 1.178, P=0.0016), tumor size (odds ratio 1.809, P<0.001), and intra-tumoral fat (odds ratio 0.515, P=0.0387) were independent variables associated with MVI. ConclusionIntra-tumoral fat detected with MR imaging may suggest lower risk for MVI of HCC and, therefore, a possibly more favorable prognosis, but the clinical value of this finding is uncertain.

Characterizing benign liver lesions and trauma with contrast-enhanced ultrasound

Microbubbles as an ultrasound contrast agent allow characterization of focal liver lesions. This article summarizes the ultrasound appearances and enhancement characteristics of benign liver lesions, focal fatty sparing and focal fatty change, and blunt liver trauma.

Time-dependent Changes and Association Between Liver Free Fatty Acids, Serum Lipid Profile and Histological Features in Mice Model of Nonalcoholic Fatty Liver Disease

Methionine-choline deficient (MCD) diet duration necessary for development of non-alcoholic fatty liver disease (NAFLD) and the dynamic of lipid profile and fatty acids are not completely established. The study examined dynamics and association between liver free fatty acids (FFA), serum lipid profile and liver morphological changes on MCD diet-induced NAFLD in mice. Male C57BL/6 mice (n= 28) were divided into four groups (n= 7 per group): control: fed with standard chow, MCD diet-fed groups: 2, 4 or 6 weeks. After treatment, liver and blood samples were taken for histopathology, serum lipid profile, and liver FFA composition. Hepatic FFA profile showed a decrease in saturated acids, arachidonic and docosahexaenoic acid, whereas proportions of docosapentaenoic, oleic and linoleic acid were increased. Total cholesterol, HDL and triglycerides progressively decreased, whereas LDL level progressively increased. Focal fatty change in the liver appeared after 2 weeks, whereas diffuse fatty change with severe inflammation and ballooned hepatocytes were evident after 6 weeks. Six-week diet model may be appropriate for investigation of the role of lipotoxicity in the progression of NAFLD. Therefore, supplementation with n-3 polyunsaturated acid like DHA, rather than DPA, especially in the initial stage of fatty liver disease, may potentially have preventive effects and alleviate development of NAFLD/NASH and may also potentially reduce cardiovascular risk by moderating dyslipidemia.

A well-differentiated hepatocellular nodular lesion in the liver of a woman

The differential diagnoses of fine needle aspiration (FNA) biopsy of a well-differentiated hepatocellular nodule (WDHN) in a woman with hepatitis B cirrhosis are discussed. Radiological diagnosis was a large regenerative nodule containing fat. <h3>Points of interest</h3> Establish representative sampling. In cirrhosis, differential diagnosis include large regenerative nodule, dysplastic nodule (low- or high-grade), and early to progressed hepatocellular carcinoma (HCC). A nodule-in-nodule lesion occurs when there is malignant transformation in a benign parent nodule. Focal nodular hyperplasia and hepatocellular adenoma are less likely. Fatty change is common in WDHNs; diagnostic pitfalls include steatosis and focal fatty change. In WDHNs, the diagnostic dilemma is proof of malignancy. Serum α-fetoprotein has low sensitivity. Key cytological features in highly well-differentiated HCC: Generally cellular aspirates; monomorphous hepatocyte population with tendency to dispersion; small monotonous tumor cells with increased nuclear-cytoplasmic ratio, nuclear crowding, and scant thick cytoplasm; transgressing but no peripheral endothelium; and lack of bile duct cells. Polymorphous hepatobiliary population +/- restoration features (such ductules) favor benign nonneoplastic WDHN, after excluding non-representative sampling. Novel immunohistochemical markers such as glypican-3, glutamine synthetase and heat shock protein 70 may be helpful as an indicator of hepatocellular malignancy if any two markers are positive. Recommend combined cytohistological approach.

Quinalphos induced oxidative stress and histoarcheitectural alterations in adult male albino rats

Quinalphos is a synthetic organophosphate used as a broad spectrum insecticide and acaricide. The present study investigates the effect of three sub-lethal doses (0.52, 1.04, 2.6mg/kg b.wt) of quinalphos for variable durations (15, 30 and 90 days) on oxidative stress and histopathological changes in adult male rats. Quinalphos treatment for 15 and 30 days resulted in a dose dependent significant increase in malondialdehyde (MDA) levels and glutathione-S-transferase (GST) activity together with a concurrent decrease in ferric reducing ability of plasma (FRAP) and glutathione (GSH) content. Quinalphos treatment for 90 days also induced a significant increase in MDA levels and GST activity but the effect was not dose-dependent. Histopathological examination of liver revealed architectural disarray and dilatation of sinusoids, focal fatty changes, accumulation of eosinophils and single cell necrosis with increasing doses. However, spleen and kidney did not show any histological changes. Administration of quinalphos resulted in oxidative stress and free radical induced injury as evidenced by increased lipid peroxidation, decreased FRAP and histopathological changes in liver.

Steatosis hepatis – eine Herausforderung?

With the increasing use of cross-sectional imaging techniques both diffuse and focal fat accumulations in the liver are frequent incidental findings. Focal fatty changes in particular, such as localized distribution disorders in steatohepatitis or focal fat deposition of the liver, can lead to difficulties in the correct diagnosis of patients with a history of malignant disease. Ultrasound is used as the first imaging modality in most cases but has a relatively low sensitivity and specificity. In most cases a further diagnosis of diffuse fatty liver accumulations is possible with non-contrast computed tomography (CT) scanning and chemical shift imaging in magnetic resonance imaging (MRI) enabling an even further differential diagnostic distinction of fatty disorders of the liver. For the detection of generalized fatty liver disease ultrasound has a sensitivity and specificity of 60-100% and 77-95%, respectively. Non-contrast CT of the liver attains a sensitivity of between 43% and 95% with a specificity of 90%. Sensitivity and specificity for chemical shift imaging of MRI are 81% and 100%, respectively. For advanced differential diagnostic distinction of the different forms of fatty liver disorders and for the correct diagnosis of benign and malignant liver lesions the leading imaging modality is chemical shift imaging of MRI (in-phase and opposed-phase).

Contrast-enhanced ultrasonography parameters in neural network diagnosis of liver tumors

To study the role of time-intensity curve (TIC) analysis parameters in a complex system of neural networks designed to classify liver tumors. We prospectively included 112 patients with hepatocellular carcinoma (HCC) (n = 41), hypervascular (n = 20) and hypovascular (n = 12) liver metastases, hepatic hemangiomas (n = 16) or focal fatty changes (n = 23) who underwent contrast-enhanced ultrasonography in the Research Center of Gastroenterology and Hepatology, Craiova, Romania. We recorded full length movies of all contrast uptake phases and post-processed them offline by selecting two areas of interest (one for the tumor and one for the healthy surrounding parenchyma) and consecutive TIC analysis. The difference in maximum intensities, the time to reaching them and the aspect of the late/portal phase, as quantified by the neural network and a ratio between median intensities of the central and peripheral areas were analyzed by a feed forward back propagation multi-layer neural network which was trained to classify data into five distinct classes, corresponding to each type of liver lesion. The neural network had 94.45% training accuracy (95% CI: 89.31%-97.21%) and 87.12% testing accuracy (95% CI: 86.83%-93.17%). The automatic classification process registered 93.2% sensitivity, 89.7% specificity, 94.42% positive predictive value and 87.57% negative predictive value. The artificial neural networks (ANN) incorrectly classified as hemangyomas three HCC cases and two hypervascular metastases, while in turn misclassifying four liver hemangyomas as HCC (one case) and hypervascular metastases (three cases). Comparatively, human interpretation of TICs showed 94.1% sensitivity, 90.7% specificity, 95.11% positive predictive value and 88.89% negative predictive value. The accuracy and specificity of the ANN diagnosis system was similar to that of human interpretation of the TICs (P = 0.225 and P = 0.451, respectively). Hepatocellular carcinoma cases showed contrast uptake during the arterial phase followed by wash-out in the portal and first seconds of the late phases. For the hypovascular metastases did not show significant contrast uptake during the arterial phase, which resulted in negative differences between the maximum intensities. We registered wash-out in the late phase for most of the hypervascular metastases. Liver hemangiomas had contrast uptake in the arterial phase without agent wash-out in the portal-late phases. The focal fatty changes did not show any differences from surrounding liver parenchyma, resulting in similar TIC patterns and extracted parameters. Neural network analysis of contrast-enhanced ultrasonography - obtained TICs seems a promising field of development for future techniques, providing fast and reliable diagnostic aid for the clinician.

Liver focal fatty changes at ultrasound after islet transplantation: an early sign of altered graft function?

Few longitudinal imaging studies of liver-engrafted islets after islet transplantation are available for islet-transplant-alone (ITA) and islet-after-kidney (IAK) transplanted patients. Particularly controversial is the link between islet function and the appearance of islet-induced liver focal fatty changes. Aims of this study were to assess liver focal fatty changes at ultrasound after islet transplantation and their relationship with islet function. The timing of first ultrasound detection of liver focal fatty changes and the prevalence and duration of these changes were assessed in 30 IAK transplanted patients, in five ITA patients and, retrospectively, in full-, partial- and no-function groups, according to islet function evaluated 1 year after transplantation. Patients with persistent ultrasound detected liver focal fatty changes underwent liver biopsy. Ultrasound positive and negative patients with functioning islets were compared for islet-function and C-peptide-levels during the follow-up. Variations of cholesterol/triglycerides and other metabolic parameters were also recorded at 1 year. Liver focal fatty changes at ultrasound were found in 12 patients (10/30 IAK, 2/5 ITA). First detection was at 6 months in eight cases and at 12 months in four cases. Liver ultrasound changes were of more than 1 year duration in eight cases. Steatosis was found histologically in 8/8 patients. At 12 months, liver ultrasound changes were detected to a greater extent in patients with partial islet function (10/12, eight IAK, two ITA) compared with patients with full islet function. C-peptide-levels were significantly lower in ultrasound-positive than in ultrasound-negative patients. At 18 months, ultrasound- positive patients were more prone to worsening of their function (9/12) compared with ultrasound-negative patients (3/18). No statistically significant differences of cholesterol/triglycerides levels were found in either the total number of patients or the IAK and ITA patients. Liver focal fatty changes at ultrasound (steatosis) after islet transplantation in IAK and ITA patients may represent an early sign of altered graft function.

Evaluation of a Focal Lesion in the Liver

Question: A 64-year-old, moderately obese female who underwent a computed tomography of her chest, including upper abdomen, for evaluation of persistent cough and sinus congestion showed an irregular, heterogenous mass in the liver involving the left lobe medial segment down to the gallbladder fossa and perhaps involving and possibly arising from the gallbladder wall. There was also some extension of the mass over the anterior aspect of the medial segment and also inferiorly anterior to the anterior segment of the right lobe. The main mass was approximately 5 cm in size (Figure A). The patient reported no symptoms related to the liver mass. She denied fevers, chills, and weight loss, and had no abdominal pain. Her past medical history was significant only for hyperlipidemia. Laboratory tests performed showed an elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of 39 and 70, respectively, and also revealed a new diagnosis of diabetes, with a glycosylated hemoglobin level of 10.1. The alpha-fetoprotein, CEA, and CA19-9 were all within normal range. What is the diagnosis? See the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. Ultrasonography of the liver (Figure B) and magnetic resonance imaging (MRI) with in- and out-of-phase images (Figure C) was performed and revealed that the mass-like lesion in the liver was due to focal fatty change.1Zezos P. Tatsi P. Nakos A. et al.Focal fatty liver sparing lesion presenting as a ”pseudotumor”: case report.Acta Gastroenterol Belg. 2006; 69: 323-326PubMed Google Scholar, 2Marin D. Iannaccone R. Catalano C. et al.Multinodular focal fatty infiltration of the liver: atypical imaging findings on delayed T1-weighted Gd-BOPTA-enhanced liver-specific MR images.J Magn Reson Imaging. 2006; 24: 690-694Crossref PubMed Scopus (15) Google Scholar, 3Alobaidi M. Shirkhoda A. Benign focal liver lesions: discrimination from malignant mimickers.Curr Probl Diagn Radiol. 2004; 33: 239-253Abstract Full Text Full Text PDF PubMed Scopus (19) Google Scholar Focal fatty infiltration can often look like a cholangiocarcinoma, gallbladder carcinoma, or metastases within the liver. The most common causes are obesity, diabetes mellitus, high alcohol consumption, and altered metabolism owing to chemotherapy. An exercise and weight loss program was recommended and she was started on metformin for her diabetes. At her follow-up visit after 3 months, the patient had lost 4.2 kg. Laboratory tests showed a normal AST of 20, a minimally elevated ALT of 32 (normal, 9–29), and a drop of the glycosylated hemoglobin from 10.1 to 6.5. A repeat MRI (Figure D) showed almost complete resolution of the area of geographic focal fat in her liver as well as the small areas in the periphery of the liver. This was probably related to her weight loss and improved glycemic control.

Incidental focal solid liver lesions: diagnostic performance of contrast-enhanced ultrasound and MR imaging

To prospectively assess the diagnostic performance of contrast-enhanced ultrasound (CEUS) and MR imaging in incidental solid focal liver lesions not characterised on ultrasound. Forty-seven patients with 50 lesions underwent MR imaging and CEUS: 24 focal nodular hyperplasias (FNH), 11 adenomas, 10 haemangiomas, 1 focal fatty change and 4 malignant lesions were identified. Two experienced radiologists randomly reviewed contrast-enhanced MR imaging and CEUS data, and provided the most likely diagnosis. Sensitivity (Se), specificity (Sp), likelihood ratios (LR) and kappa value were calculated. A histotype diagnosis was obtained in 66-52% with MR imaging and 52-53% with CEUS, respectively, for both readers. Se, Sp and LR for haemangioma were 100-100, 100-100 and 78-78 with MR imaging and 89-89, 100-100 and 68-70 with CEUS; for FNH with MR imaging they were 88-63, 96-100 and 23-34 and 74-67, 88-96 and 6-17 with CEUS. If the diagnosis of haemangioma was uncertain with CEUS, MR imaging always confirmed the diagnosis. If the diagnosis of FNH was uncertain with either CEUS or MR imaging, the other imaging technique confirmed the diagnosis in approximately half the cases. Both CEUS and MR imaging have a high diagnostic performance in incidental focal liver lesions and are complementary when diagnosis is uncertain.

Discrete Hypoechoic Ring in Hepatic Cavernous Hemangioma Resembling a Malignant Tumor: Correlation with Histologic Features

Differential diagnoses of hepatic nodules include hepatocellular carcinoma, focal nodular hyperplasia, hepatic adenoma, regenerative nodule, focal fatty changes, and hemangioma. However, differentiation of these nodules can often be difficult. Hemangiomas are frequently encountered during ultrasonogram incidentally and can be diagnosed easily because they have an almost distinctive sonographic appearance: a homogeneous hyperechogenicity and discrete posterior acoustic enhancement. They also sometimes have atypical findings, for example an internal echogenicity including hypoechogenicity, heterogeneous echogenicity, hyperechoic rim, central hypoechogenicity due to various changes (e.g., internal hemorrhage, necrosis, thrombosis, myxomatous change, and fibrosis), and (rarely) calcification. We report herein the case of an atypical hemangioma presenting with a hypoechoic peripheral ring, mimicking a hepatic malignancy. To our knowledge, there have been no other reports demonstrating a cavernous hemangioma with a discrete hypoechoic ring and without a pseudocapsule.

Steatosis is a lot more than holes in hepatocytes

Chronic hepatitis C infection remains a common and significant cause of liver disease leading to end-stage cirrhosis and liver failure. It is also a common indication for the necessity of a liver transplant. Histologically, chronic inflammation and fibrosis are characteristic features of this disease. The stage and grade of the disease process is measured by the amount of fibrosis and severity of the inflammation. Focal fatty change is a known histological finding of hepatitis C infection. However, the exact significance of such a finding is not clear. In this issue, Zubair et al.[1] demonstrated that the presence of fat, especially macrovesicular steatosis, is associated with a higher stage of fibrosis. They used a routine histological analysis as well as a morphometric evaluation to demonstrate an association. The authors suggested that such fat may result from mitochondrial oxidative stress. Hence, along with viral infection and inflammation, the presence of fat may also modulate the progression of this disease. Fat accumulation is known to cause fibrosis in alcoholic and non alcoholic fatty liver disease. Such changes may occur due to the release of adipocytokines causing tissue damage.[2–4] In addition, mitochondrial oxidative stress may lead to the activation of proinflammatory and fibrogenic factors.[5–7] It is, however, interesting to note that only macrovesicular steatosis has a pronounced effect on an advanced hepatitis C induced lesion. This point is of significant interest from a pathogenetic point of view. However, although this study was not designed to answer the reasons behind such findings, it suggested a possible relationship. In previous studies, it has been shown that serum HCV RNA levels correlate with histological liver damage and concur with steatosis and a high viral load acts together with steatosis in accelerating the progression of liver injury.[8] In an earlier study, this group had also demonstrated that patients with genotype 3a showed a significantly higher prevalence of steatosis compared with those infected with other genotypes.[9] In another study, although hepatic steatosis was not associated with HCV RNA levels, it was associated with being overweight, hepatic fibrosis, and triglyceride levels in chronic hepatitis C infection.[10] Nevertheless, an inevitable question that may arise is whether an assessment of a change in fat is to be included in a routine pathology report to determine a prognosis. This is not easy to answer. However, larger multi-center studies may be required to address such questions. A large-scale study with a detailed clinico-pathological correlation may provide valuable insight. Furthermore, investigations as to the specific mechanisms by which only macrovesicular fat causes tissue damage are very important. Such analysis may have far reaching implications and may also be of importance in other liver diseases associated with fat accumulation in the hepatocytes. Understanding pathogenetic mechanisms is fascinating but a difficult undertaking. Extensive basic science research is needed to address these questions. We need to have concerted efforts involving hepatologists, pathologists, translational researchers, and basic scientists to identify such pathogenetic mechanisms since only a better understanding of such pathogentic mechanisms will lead to the development of specific treatment for advanced tissue damage in hepatitis.

Focal Fat Spared Area in the Liver Masquerading as Hepatic Metastasis on F-18 FDG PET Imaging

Fatty infiltration of the liver is not an uncommon imaging finding with modalities like ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). However, when it manifests as a focal fatty change or areas of focal fat sparing, an appearance of a mass lesion is produced. Focal tracer uptake seen in the liver on F-18 fluorodeoxyglucose-positron emission tomography (FDG-PET) when it is performed as a part of a metastatic work up for colorectal cancer is highly suggestive of hepatic metastasis. We present an unusual finding of focal FDG uptake in a fat-spared area in the liver masquerading as a hepatic metastasis.