Magnetic resonance iron-free nodules in genetic hemochromatosis

MRI Appearance of Focal Lesions in Liver Iron Overload

Liver iron overload is defined as an accumulation of the chemical element Fe in the hepatic parenchyma that exceeds the normal storage. When iron accumulates, it can be toxic for the liver by producing inflammation and cell damage. This can potentially lead to cirrhosis and hepatocellular carcinoma, as well as to other liver lesions depending on the underlying condition associated to liver iron overload. The correct assessment of liver iron storage is pivotal to drive the best treatment and prevent complication. Nowadays, magnetic resonance imaging (MRI) is the best non-invasive modality to detect and quantify liver iron overload. However, due to its superparamagnetic properties, iron provides a natural source of contrast enhancement that can make challenging the differential diagnosis between different focal liver lesions (FLLs). To date, a fully comprehensive description of MRI features of liver lesions commonly found in iron-overloaded liver is lacking in the literature. Through an extensive review of the published literature, we aim to summarize the MRI signal intensity and enhancement pattern of the most common FLLs that can occur in liver iron overload.

MR Imaging of Diffuse Liver Disease

The liver performs many vital functions for the human body. It stores essential vitamins and minerals, such as iron and vitamins A, D, K, and B₁₂. It synthesizes proteins, such as blood clotting factors, albumin, and glycogen, as well as cholesterol, carbohydrates, and triglycerides. Additionally, it acts as a detoxifier, metabolizing and helping to clear alcohol, drugs, and ammonia. Typical MR imaging protocols for liver imaging include T2-weighted, chemical shift imaging, and precontrast and postcontrast T1-weighted sequences. This article discussed MR imaging of diffuse liver diseases and their typical imaging findings.

Periodontal status and serum biomarker levels in HFE haemochromatosis patients. A case-series study

AIM

To investigate the association between periodontal status and serum biomarkers in patients with HFE haemochromatosis.

MATERIAL AND METHODS

This clinical case series included 84 HFE-C282Y homozygous patients. Periodontal evaluation was performed using clinical attachment level, probing depth, gingival bleeding index, visible plaque index and gingival index. Serum markers of iron metabolism were collected from medical records. The relationship between serum biomarkers of iron burden and the severity of periodontitis was investigated.

RESULTS

The study population consisted of 47 men and 37 women, routinely treated in the Unit of Hepatology, University Hospital, Rennes. All patients presented with periodontitis (mild: n = 1, moderate: n = 37 and severe: n = 46). There was a positive association between transferrin saturation >45% and the severity of periodontitis (adjusted odds ratio = 5.49, p = .002).

CONCLUSION

Severe periodontitis is associated with the severity of iron burden in patients with HFE-related hereditary haemochromatosis. Dental examination should be included in the initial assessment of all these patients.

Improving Detection of Iron Deposition in Cirrhotic Liver Using Susceptibility-Weighted Imaging With Emphasis on Histopathological Correlation

OBJECTIVE

The aim of this study was to investigate the value of susceptibility-weighted imaging (SWI) for detection and quantification of iron deposition in cirrhotic liver.

METHODS

Fifty-five cirrhotic patients underwent hepatic magnetic resonance imaging examination including SWI and multiecho T2*-weighted imaging (T2*WI). Detection of iron deposition and number of siderotic nodules were compared between SWI and T2*WI. Correlation among SWI phase value, T2* value, and hepatic iron concentration were determined.

RESULTS

Susceptibility-weighted imaging significantly improved detection of iron deposition compared with T2*WI (90.7% vs 66.7%, P = 0.002), attributing to grade 1 (73.3% vs 26.7%, P = 0.027) and grade 2 (93.8% vs 56.3%, P = 0.037). Iron deposition of grade 3 and 4 could be detected by both SWI and T2*WI. The number of siderotic nodules visualized on SWI was significantly larger than that on T2*WI (107.5 ± 7.4 vs 62.7 ± 4.6, P = 0.002). There were significantly negative correlation between phase value and iron score (r = -0.803), and positive correlation between phase value and T2* value (r = 0.771).

CONCLUSIONS

Susceptibility-weighted imaging can improve detection of minimal and mild iron deposition in cirrhotic liver.

Haemochromatosis

Haemochromatosis is now known to be an iron-storage disease with genetic heterogeneity but with a final common metabolic pathway resulting in inappropriately low production of the hormone hepcidin. This leads to increase in intestinal absorption and deposition of excessive amounts of iron in parenchymal cells which in turn results in eventual tissue damage and organ failure. A clinical enigma has been the variable clinical expression with some patients presenting with hepatic cirrhosis at a young age and others almost asymptomatic for life. Research is unravelling this puzzle by identifying environmental factors-especially alcohol consumption-and associated modifying genes that modulate phenotypic expression. A high index of suspicion is required for early diagnosis but this can lead to presymptomatic therapy and a normal life expectancy. Venesection (phlebotomy) therapy remains the mainstay of therapy, but alternative therapies are the subject of current research.

Detection of Endogenous Iron Reduction during Hepatocarcinogenesis at Susceptibility-Weighted MR Imaging: Value for Characterization of Hepatocellular Carcinoma and Dysplastic Nodule in Cirrhotic Liver

Objective

To investigate the value of susceptibility-weighted imaging (SWI) for characterization of hepatocellular carcinoma (HCC) and dysplastic nodule (DN).

Materials and Methods

Sixty-eight cirrhotic patients with 89 hepatocellular nodules underwent SWI. The radiological features of hepatocellular nodules on SWI were classified into three types: type A (iso- or hypointensity, and background liver siderosis), type B (hyperintensity, and background liver siderosis), or type C (hyperintensity, and no background liver siderosis). Intranodular and background liver iron content was quantified and correlated with SWI pattern. Prussian blue staining was performed to quantify intranodular and background liver iron content.

Results

Type A pattern (n = 12) contained 11 (91.7%) DNs and 1 (8.3%) HCC, Type B pattern (n = 66) comprised 1 (1.5%) DN and 65 (98.5%) HCCs (including 12 DN-HCCs and 53 overt HCCs), and type C pattern (n = 11) was exclusively seen in HCCs. The iron scores of DN-HCCs and overt HCCs were significantly lower than those of background livers [(0.091±0.30) VS (2.18±0.87), P = 0.000; (0.11±0.41) VS (2.16±0.97), P = 0.000; respectively]. There was no significant difference between iron scores of DNs and those of background livers [(1.92±0.29) VS (2.17±039), P = 0.191]. For lesion-based and patient-based analysis of HCCs (DN-HCCs and overt HCCs), type B pattern showed a sensitivity, specificity, accuracy, positive predicative value (PPV), and negative predicative value (NPV) of 84.4% and 84.4%, 91.7% and 75%, 85.4% and 83.8%, 98.5% and 98.2%, 47.8% and 23.1%, respectively.

Conclusion

SWI can provide valuable information for characterization of HCC and DN based on endogenous iron reduction during hepatocarcinogenesis.

Liver transplantation to treat suspected hepatocellular carcinoma in iron-free foci in congenital hemochromatosis: case report

Hepatocellular carcinoma (HCC) commonly develops in cirrhotic or noncirrhotic livers affected by congenital hemochromatosis. In patients with congenital hemochromatosis and HCC, liver transplantation is a therapeutic option with a 5-year posttransplantation survival rate as high as 80%. Herein is reported congenital hemochromatosis in a 37-year-old man. During a routine checkup, 2 liver nodules were detected. Signal characteristics at magnetic resonance imaging indicated the presence of iron-free foci (IFF). The serum α-fetoprotein concentration was within the range of normal, and repeated liver biopsy did not show histomorphologic signs of malignancy but confirmed the presence of IFF in surrounding siderosis. The patient was listed for liver transplantation with match MELD (Model of End-Stage Liver Disease including exceptions) because of suspected HCC. After 173 days on the waiting list, liver transplantation was performed successfully. Histologic examination of the explanted liver confirmed 2 HCC lesions with a diameter of 0.9 cm in the exact projection as the IFF detected at magnetic resonance imaging. At 20 months of rapamycin-based immunosuppression therapy, there were no signs of HCC recurrence. This is, to our knowledge, the first report of liver transplantation performed to treat suspected HCC based on the finding of IFF in congenital hemochromatosis, with histopathologic confirmation of the diagnosis of HCC after transplantation. According to this case and the current literature, IFF in patients with congenital hemochromatosis should be considered preneoplastic lesions vulnerable to possible development of HCC.

Non-invasive methods for liver fibrosis prediction in hemochromatosis: One step beyond

Advances in recent years in the understanding of, and the genetic diagnosis of hereditary hemochromatosis (HH) have changed the approach to iron overload hereditary diseases. The ability to use a radiologic tool (MRI) that accurately provides liver iron concentration determination, and the presence of non-invasive serologic markers for fibrosis prediction (serum ferritin, platelet count, transaminases, etc), have diminished the need for liver biopsy for diagnosis and prognosis of this disease. Consequently, the role of liver biopsy in iron metabolism disorders is changing. Furthermore, the irruption of transient elastography to assess liver stiffness, and, more recently, the ability to determine liver fibrosis by means of MRI elastography will change this role even more, with a potential drastic decline in hepatic biopsies in years to come. This review will provide a brief summary of the different non-invasive methods available nowadays for diagnosis and prognosis in HH, and point out potential new techniques that could come about in the next years for fibrosis prediction, thus avoiding the need for liver biopsy in a greater number of patients. It is possible that liver biopsy will remain useful for the diagnosis of associated diseases, where other non-invasive means are not possible, or for those rare cases displaying discrepancies between radiological and biochemical markers.

Relation of hemochromatosis with hepatocellular carcinoma: epidemiology, natural history, pathophysiology, screening, treatment, and prevention

HH is a common inherited disorder of iron metabolism affecting about 1 out of 250 individuals of Northern European decent. Many of these patients do not have evident phenotypic expression and do not develop significant iron loading. Some patients, however, develop progressive iron overload and cirrhosis. These individuals are at risk of developing HCC. Cirrhotics with hemochromatosis should undergo regular screening for HCC. If HCC is identified early, treatment with either resection or liver transplantation is optimal. Palliative measures, including ablative therapy and chemoembolization, can be used. With increasing clinical recognition,hemochromatosis should be diagnosed earlier and progression to cirrhosis and HCC should be minimized.

Preneoplastic lesions in human hepatocarcinogenesis

The early stages of hepatocarcinogenesis in human chronic liver diseases are characterized by the emergence of preneoplastic lesions of which some will eventually develop into hepatocellular carcinoma (HCC). Basic studies on the genetic and epigenetic alterations of these preneoplastic lesions may eventually lead to new therapeutic strategies. Clinicopathological studies are also important in order to determine optimal management of patients with a preneoplastic lesion. This article aims to provide a comprehensive review of the current concepts of preneoplastic lesion in chronic liver diseases. The microscopical small-cell dysplastic focus is the smallest morphologically recognizable precursor lesion of HCC and therefore is a logical target of study to elucidate the earliest events in hepatocarcinogenesis. In contrast, large-cell dysplasia is not a precursor lesion, but appears to be of clinical value because of its good predictive value for development of HCC. Dysplastic nodules (DNs) are macroscopically recognizable precursor lesions of HCC and high-grade DNs (HGDNs) have a risk of malignant transformation. Detection of DNs and correct differentiation from small HCC (<2 cm) is sometimes difficult, especially when only imaging techniques are used. Additional clinicopathological studies on identification and optimal treatment of DNs are necessary. Molecular studies on HGDNs and small HCCs may yield much information on the genetic mechanisms involved in the transition from severe dysplasia to early malignancy. In contrast, currently available data indicate that (large) regenerative nodules do not represent a distinct step in hepatocarcinogenesis. Animal models will be helpful in the further unravelling of human HCC development, provided that studies are performed on models that are good representatives of human hepatocarcinogenesis. We propose three criteria by which good mimickers can be identified.

MR Imaging of Hepatocellular Carcinoma Arising in Genetic Hemochromatosis

A case of a 51-year-old male with previously unsuspected genetic hemochromatosis (GH) associated with hepatocellular carcinoma (HCC), for which MR imaging was useful in diagnosis, is presented. Contrast-enhanced ultrasonography depicted a mass in segment 8 of the liver and a liver tumor was suspected. The mass could not be revealed on unenhanced or enhanced CT examination. MR imaging with unenhanced T1-weighted FLASH and T2-weighted gradient echo sequences clearly depicted the tumor; the tumor appeared hyperintense against a background of low hepatic signal intensity caused by iron overload. The iron-overloaded liver provided a natural source of paramagnetic contrast for detection of HCC. Studies are required to further assess the accuracy of these sequences in detection of HCC in patients with GH.

Review article: haemochromatosis

Hereditary haemochromatosis is the prototype disease for primary iron overload. The disorder is very common, especially amongst subjects of Northern European extraction. It is characterized by an autosomal recessive mode of inheritance, and most cases are homozygous for the C282Y mutation in the HFE gene. Haemochromatosis is now recognized to be a complex genetic disease with probable significant environmental and genetic modifying factors. The early diagnosis of individuals at risk for the development of haemochromatosis is important, because survival and morbidity are improved if phlebotomy therapy is instituted before the development of cirrhosis. The cost-effectiveness and utility of large-scale screening for haemochromatosis have been questioned given that many individuals with the homozygous C282Y mutation do not have iron overload or end-organ damage. However, the use of phenotypic tests, such as serum transferrin-iron saturation, for initial screening avoids the problem of the identification of non-expressing homozygotes. Liver biopsy remains important in management to determine the presence or absence of cirrhosis, particularly amongst patients with serum ferritin levels greater than 1000 ng/mL or elevated liver enzymes. Those with non-HFE haemochromatosis who cannot be identified on genotypic testing should have a liver biopsy to establish diagnosis. Patients with end-stage liver disease may develop liver failure or primary liver cancer, and liver transplantation may be required. Liver transplantation for haemochromatosis is associated with a poorer outcome compared with other indications because of infections and cardiac complications.

[Hereditary hemochromatosis]

INTRODUCTION

Hereditary hemochromatosis is a fairly common disease in the Caucasian population, with a prevalence estimated at between 1.5 to 3/1,000 inhabitants. Over the past few years, its symptomatology has altered; at present, its clinical aspect with diabetes mellitus, cirrhosis, and darker skin pigmentation only constitutes 10% of new cases of this disease.

CURRENT KNOWLEDGE AND KEY POINTS

In 1996, the discovery of the C282Y mutation in the HFE gene radically altered the diagnostic approach to hereditary hemochromatosis. At present, any patient admitted with an isolated case of asthenia, or with arthralgia or hypertransaminasemia should be examined via transferrin-saturation testing: if the transferrin saturation coefficient is > 45%, then the presence of the C282Y mutation should be investigated to confirm the diagnosis of hemochromatosis. A liver biopsy is no longer necessary to establish the diagnosis, but this is still useful in cases of possible cirrhosis, which is the main risk factor for hepatocellular carcinoma. Phlebotomy remains the sole recommended treatment, and should be undertaken in a case-specific manner. Family screening should be carried out for all first-degree relatives for every new case that is diagnosed.

FUTURE PROSPECTS AND PROJECTS

The discovery of the HFE gene has permitted hereditary hemochromatosis to be easily differentiated from other forms of hepatic iron overload including a new syndrome, dysmotabolic hepatosiderosis. Casos of homozygotic C282Y without hepatic iron overload have been described, but the clinical outcome of some of these cases requires further study, and adds to the controversy on whether systematic population screening should be made available.