Focal eosinophilic infiltration in the liver: radiologic findings and clinical course

Eosinophilic Disorders of the Gastrointestinal Tract and Associated Abdominal Viscera: Imaging Findings and Diagnosis

Eosinophilic gastrointestinal disorders (EGIDs) are inflammatory conditions of the gastrointestinal tract that are characterized by tissue eosinophilia and end-organ dysfunction or damage. Primary EGIDs are associated with atopy and other allergic conditions, whereas secondary EGIDs are associated with underlying systemic diseases or hypereosinophilic syndrome. Within the spectrum of EGIDs, eosinophilic esophagitis is the most prevalent. Eosinophilic gastroenteritis and eosinophilic colitis are relatively uncommon. Eosinophilic infiltration of the liver, biliary tree, and/or pancreas also can occur and mimic other inflammatory and malignant conditions. Although endoscopic evaluation is the method of choice for eosinophilic esophagitis, radiologic evaluation of the esophagus plays an important role in the assessment of disease severity. CT and MR enterography are the modalities of choice for demonstrating specific forms of eosinophilic gastroenteritis. CT and MRI are important in the detection of abdominal visceral involvement in EGIDs. Diagnosis is often challenging and relies on symptoms, imaging findings, histologic confirmation of tissue eosinophilia, and correlation with peripheral eosinophilia. Imaging is crucial for identifying characteristic organ-specific findings, although imaging findings are not specific. When promptly treated, EGIDs usually have a benign clinical course. However, a delayed diagnosis and associated surgical interventions have been associated with morbidity. Therefore, a radiologist's knowledge of the imaging findings of EGIDs in the appropriate clinical settings may aid in early diagnosis and thereby improve patient care. An overview of the clinical features and imaging findings of EGIDs and the eosinophilic disorders of associated abdominal viscera is provided. Online supplemental material is available for this article. ^©RSNA, 2022.

Hypereosinophilia with Hepatic Nodule Formation Caused by Ganoderma lucidum

A 61-year-old man who underwent surgery for rectal adenocarcinoma developed multiple hepatic nodules. The nodules were 1-3 cm without a capsular structure or contrast enhancement on computed tomography/magnetic resonance imaging, findings that were atypical for adenocarcinoma metastases. A biopsy showed the aggregation of eosinophils without larval bodies, ova, or granulomas. Laboratory tests showed a marked increase in eosinophils and a slight liver enzyme elevation. He had been taking the commercial herbal medicine Ganoderma lucidum for his liver function. After discontinuing G. lucidum, the eosinophil counts and liver enzyme levels rapidly resolved, and the nodules disappeared completely. This is a rare case of hypereosinophilia with hepatic nodules reactive to herbal medicine rather than a parasitic infection.

Atypical Appearance of Hepatocellular Carcinoma and Its Mimickers: How to Solve Challenging Cases Using Gadoxetic Acid-Enhanced Liver Magnetic Resonance Imaging

Hepatocellular carcinoma (HCC) can be diagnosed noninvasively with contrast-enhanced dynamic computed tomography, magnetic resonance imaging, or ultrasonography on the basis of its hallmark imaging features of arterial phase hyperenhancement and washout on portal or delayed phase images. However, approximately 40% of HCCs show atypical imaging features, posing a significant diagnostic challenge for radiologists. Another challenge for radiologists in clinical practice is the presentation of many HCC mimickers such as intrahepatic cholangiocarcinoma, combined HCC-cholangiocarcinoma, arterioportal shunt, and hemangioma in the cirrhotic liver. The differentiation of HCCs from these mimickers on preoperative imaging studies is of critical importance. Hence, we will review the typical and atypical imaging features of HCCs and the imaging features of its common mimickers. In addition, we will discuss how to solve these challenges in practice.

FOLFOX and capecitabine-induced hepatic granuloma mimicking metastasis in a rectal cancer patient

A 49-year-old male carcinoma rectum patient was treated with neoadjuvant FOLFOX (folinic acid, fluorouracil (5-FU) and oxaliplatin) chemotherapy, chemoradiotherapy with capecitabine, surgery and adjuvant FOLFOX. On follow-up, the patient developed a metabolically active liver lesion mimicking metastasis. Liver biopsy and histopathology showed sinusoidal dilatation with non-caseating granulomas. Follow-up fluorodeoxyglucose positron-emission tomography CT scan demonstrated increase in size of the lesion with metabolic activity suspicious of metastasis. The patient underwent segmental liver resection and histopathology showed non-necrotising granuloma with no evidence of malignancy. It is crucial to consider potential side effects of chemotherapeutic agents and have an unbiased approach when evaluating new liver lesions during post treatment follow-up of colorectal cancer. A multidisciplinary tumour board approach comprising of gastroenterologists, medical oncologists, pathologists, radiologists and surgeons is suggested in the management of such patients. The patient is currently doing well and on regular follow-up.

Non-neoplastic hepatopancreatobiliary lesions simulating malignancy: can we differentiate?

Despite the success of cross-sectional imaging in evaluating hepatopancreatobiliary system malignancies, several non-malignant disease processes may closely mimic malignancy. Differentiating these benign diseases from malignancy may be difficult, or even impossible, even in the hands of experienced imagers. In this manuscript, we present benign mimics involving the hepatopancreatobiliary system and try to increase awareness of these potential pitfalls.

What Are the Clinical Features and Etiology of Eosinophilic Liver Infiltration?

Background/Aims

Although eosinophilic liver infiltration (ELI) is not rare, few data exist regarding its clinical characteristics and etiology. Therefore, we evaluated these aspects to better understand the clinical implications of this lesion type, which is reasonably common in Korea.

Methods

Patients suspected of having ELI, based on abdominal computed tomography results obtained between January 2010 and September 2017, were enrolled in this retrospective study. The presumptive etiologies of ELI were categorized as parasite infections, hypereosinophilic syndrome (HES), eosinophilic granulomatosis with polyangiitis (EGPA), malignancies, and unidentified. Clinical courses and treatment responses were also evaluated.

Results

The mean age of the enrolled patients (male, 237/328) was 62 years. Most patients (63%) were diagnosed incidentally and had peripheral eosinophilia (90%). Only 38% of the enrolled patients (n=126) underwent further evaluations to elucidate the etiology of the suspected ELI; 82 (25%) had parasite infections, 31 (9%) had HES, five (2%) had EGPA, and five (2%) had drug reactions in conjunction with eosinophilia and systemic symptoms. Almost half of the other enrolled patients had cancer. Radiologic resolution was achieved in 191 patients (61%; median time to radiologic resolution, 185 days). Resolution of peripheral eosinophilia was achieved in 220 patients (79%). In most cases, the course of ELI was benign.

Conclusions

This large ELI study is unique in that the incidence rate, underlying diseases, and clinical courses were comprehensively evaluated. Clinicians should investigate the etiology of ELI, as several of the underlying diseases require intervention rather than observation.

CT and MRI findings in focal eosinophilic infiltration of the liver

OBJECTIVES

To investigate the findings of computed tomography (CT) and magnetic resonance imaging (MRI) of focal eosinophilic infiltration (FEI) of the liver.

METHODS

A retrospective study including 29 patients with confirmed FEI of the liver was performed. We evaluated the lesions' number, distribution, size, shape, margin, attenuation or signal intensity characteristics, the enhancement pattern, and some special features. Spearman correlation analysis was used to analyze the correlation between the number of lesions and the eosinophil counts in peripheral blood.

RESULTS

In all, 108 lesions were detected in 29 cases, including two cases with single lesion and the remaining 27 cases with multiple lesions. The mean size of all lesions was 34 mm (range, from 3 to 61 mm). 95 (88%) lesions were located in subcapsular parenchyma or surrounding the portal vein. Most (66%) subcapsular lesions were wedge shaped and all lesions surrounding portal vein were round shaped. However, the hepatic parenchymal lesions were irregular or round shaped. All lesions showed ill-defined margins. On pre-contrast CT images, the lesions showed slightly low attenuation or iso-attenuating. On T1-weighted and T2-weighted images, the lesions were slightly iso-/hypointense and hyperintense, respectively. A total of 23 (79.3%) cases were gradually enhanced. Branches of portal vein went through the lesions in all cases; 12 had 'stripe sign' and 16 had 'halo ring sign.' Spearman analysis indicated a significant correlation between the number of lesions and the increased eosinophils in peripheral blood (r = 0.627, p = 0.0003).

CONCLUSIONS

Special CT and MRI features and increased eosinophils may strongly suggest the diagnosis of FEI of the liver.

Hepatic Lesions that Mimic Metastasis on Radiological Imaging during Chemotherapy for Gastrointestinal Malignancy: Recent Updates

During chemotherapy in patients with gastrointestinal malignancy, the hepatic lesions may occur as chemotherapy-induced lesions or tumor-associated lesions, with exceptions for infectious conditions and other incidentalomas. Focal hepatic lesions arising from chemotherapy-induced hepatopathies (such as chemotherapy-induced sinusoidal injury and steatosis) and tumor-associated eosinophilic abscess should be considered a mimicker of metastasis in patients with gastrointestinal malignancy. Accumulating evidence suggests that chemotherapy for gastrointestinal malignancy in the liver has roles in both the therapeutic effects for hepatic metastasis and injury to the non-tumor bearing hepatic parenchyma. In this article, we reviewed the updated concept of chemotherapy-induced hepatopathies and tumor-associated eosinophilic abscess in the liver, focusing on the pathological and radiological findings. Awareness of the causative chemo-agent, pathophysiology, and characteristic imaging findings of these mimickers is critical for accurate diagnosis and avoidance of unnecessary exposure of the patient to invasive tissue-based diagnosis and operations.

Enhanced resolution of eosinophilic liver abscess associated with toxocariasis by albendazole treatment

BACKGROUND/AIMS

Visceral larva migrans, caused by Toxocara canis and Toxocara cati, has emerged as a significant cause of eosinophilic liver abscess (ELA). Differentiation of ELA associated with toxocariasis (ELA-T) from metastasis or primary liver malignancy is sometimes difficult. However, the role of albendazole treatment remains uncertain in this condition. The aim of this study was to evaluate whether albendazole can enhance the radiologic resolution of ELA-T.

METHODS

We retrospectively reviewed the medical records of the patients diagnosed with ELA-T at our institution between January 2008 and December 2011. ELA-T was diagnosed based on the imaging findings on computed tomography or magnetic resonance imaging and the presence of positive serum IgG antibody for Toxocara canis. Among a total of 163 patients, 32 patients received albendazole (albendazole group) and 131 did not (control group). Baseline characteristics and fate of liver nodules were compared between the two groups.

RESULTS

Baseline characteristics (age, sex, number and maximal size of lesions, eosinophil count) were similar between the two groups. Median duration for achieving radiologic resolution in the albendazole group was significantly shorter than in the control group (207 days [range 186-228] vs. 302 days [range 224-380], p=0.023). In Cox regression analysis of the cumulative rates of radiologic resolution, the hazard ratio for albendazole treatment was 1.99 (95% confidence interval, 1.22-3.23).

CONCLUSIONS

Radiologic resolution of ELA-T can be accelerated with albendazole treatment. Hence, inconvenience associated with long-term follow-up and unnecessary worries among patients can be eliminated with albendazole treatment.

Hepatic visceral larva migrans, a resilient entity on imaging: Experience from a tertiary liver center

INTRODUCTION

Hepatic visceral larva migrans (VLM) is an uncommon parasitic manifestation seen in the liver. It presents as coalescing, conglomerated, or solitary abscess cavities in the liver on imaging. We conducted a retrospective clinico-radiological analysis of 24 patients with biopsy proven VLM who were reviewed and followed up at our tertiary liver institute over a period of 4 years.

MATERIALS AND METHODS

The study was performed to correlate the radiological features and imaging response to therapy for hepatic VLM. The disease course, imaging findings, progressive, absolute eosinophil counts (AEC), hydatid serology, and the extent of radiological regression of the liver lesions, on follow-up were analyzed.

RESULTS

Imaging showed a diagnostic accuracy of 42%. Hydatid serology was positive in 46% patients before starting treatment. The median pretreatment AEC of 507 showed a significant posttreatment AEC decline to median value of 117. The Wilcoxon signed ranks test showed significant decline in the AEC (P < 0.001). Radiological regression was present in all lesions. However, patients showed residual abscesses on imaging, up to 2 years on follow-up.

CONCLUSION

This study reveals that AEC has a significant predictive value in diagnosis and as a marker for disease regression. Complete radiological resolution of hepatic lesions does not correlate with total clinical remission. This finding warrants the need for further studies to look into the role of prolonged medical therapy or surgery as an alternate to current therapy module in cases of hepatic visceral larva abscesses.

Clinical characteristics that distinguish eosinophilic organ infiltration from metastatic nodule development in cancer patients with eosinophilia

BACKGROUND

When new space-occupying lesions are observed together with peripheral blood eosinophilia in patients diagnosed with cancer, the possibility of eosinophilic organ involvement should be differentiated from metastasis of primary cancer, since a misdiagnosis could lead to unnecessary chemotherapy. The aim of this study is to identify the clinical characteristics of eosinophilic organ involvement that distinguish it from distant metastasis in patients with primary cancer.

METHODS

The medical records of 43 cancer patients who developed hepatic or pulmonary nodules with peripheral blood eosinophilia between January 2005 and February 2010 in the Asan Medical Center (Seoul) were reviewed. Eosinophilic infiltration and distant metastasis were identified on the basis of pathological findings and radiological features. Fisher's exact test, χ² test or Mann-Whitney test were used for statistical analysis.

RESULTS

In total, 33 patients (76%) were diagnosed with eosinophilic infiltration, 5 (12%) with cancer metastasis and 5 (12%) had undetermined diagnoses. Compared to the patients with metastases, the patients with eosinophilic infiltration were significantly more likely to have serology indicating a parasitic infection, a history of eating raw food, high serum levels of total IgE, normal liver function, normal C-reactive protein levels, a normal erythrocyte sedimentation rate, and fewer and smaller nodules. The most common underlying malignancy in the eosinophilic organ infiltration group was stomach cancer. Physicians tended to neglect the eosinophilia in patients with a history of cancer.

CONCLUSIONS

Several clinical characteristics of eosinophilic organ infiltration distinguish it from cancer metastasis. Physicians should make greater efforts to determine the causes of organ involvement with peripheral blood eosinophilia, especially in cancer patients.

Differentiating focal eosinophilic infiltration from metastasis in the liver with gadoxetic acid-enhanced magnetic resonance imaging

Objective

To determine the most useful findings of gadoxetic acid-enhanced 3.0 Tesla (T) MRI for differentiating focal eosinophilic infiltration (FEI) from hepatic metastasis with verification of their usefulness.

Materials and Methods

Pathologically or clinically proven 39 FEIs from 25 patients and 79 hepatic metastases from 51 patients were included in the study. Gadoxetic acid-enhanced 3.0T MRI was performed in all cancer patients. Size differences measured between T2-weighted and hepatobiliary-phase images for lesions > 1 cm and morphologic findings (margin, shape, signal intensity on T1- and T2-weighted images, enhancement pattern on dynamic images, and target appearance on hepatobiliary-phase images) were compared between two groups via Student's t test as well as univariate and multivariate analyses. Diagnostic predictive values of two observers for differentiating two groups were assessed before (session 1) and after (session 2) recognition of results.

Results

Mean size difference (2.1 mm) in FEIs between the two images was significantly greater than for metastases (0.7 mm) (p < 0.05). An ill-defined margin and isointensity on T1-weighted images were independently significant morphologic findings (p < 0.05) for differentiating the two groups. All observers achieved a higher diagnostic accuracy in session 2 (97% and 98%) than session 1 (92% and 89%) with statistical significance in observer 2 (p < 0.05). All observers had significantly higher sensitivities (95%) and negative predictive values (NPVs) (98%) in session 2 than in session 1 (sensitivity, 74% in two observers; NPV, 89% and 88%) (p < 0.05).

Conclusion

With the size change, an ill-defined margin and isointensity on T1-weighted images are the most useful findings for differentiating FEI from hepatic metastasis on gadoxetic acid-enhanced 3.0T MRI.

Clinical features of clinically diagnosed eosinophilic liver abscesses

PURPOSE

Eosinophilic liver abscesses (ELAs) are frequently encountered in the clinical field based on typical computed tomography (CT) findings and the presence of peripheral eosinophilia. In this study, the authors evaluated the clinical features and natural course of CT diagnosed ELAs.

METHODS

The medical records of patients that underwent abdominal CT from July 2004 to February 2008 at Seoul National University Hospital were retrospectively evaluated. ELA was clinically diagnosed by the presence of peripheral eosinophilia (≥500 μL(-1)) and typical CT findings. The presumptive causes of clinically diagnosed ELA were divided into three categories, namely, parasitic infections, malignancies, and unidentified etiologies. Clinical courses and responses to treatment were evaluated.

RESULTS

Clinically diagnosed ELAs were identified in 164 patients and the incidence of ELA was 0.68%. Of these patients, 118 (71.9%) showed radiologic resolution of clinically diagnosed ELA at a median 6.2 (0.2-33.1) months. In addition, 79 (48.2%) patients also achieved normalization of peripheral eosinophilia with radiologic resolution of clinically diagnosed ELA. In patients without identified etiologies, mean time to radiologic resolution was significantly shorter for patients treated empirically with an anti-parasitic drug than for those not treated [4.4 (0.9-26.3) vs. 12.2 (1.5-33.2) months, median (range), P = 0.001].

CONCLUSIONS

Clinically diagnosed ELA adopts a relatively benign course. Empirical anti-parasitic treatment in patients without an identified etiology may shorten the duration of clinically diagnosed ELA.

Focal eosinophilic infiltration of the liver: gadoxetic acid-enhanced magnetic resonance imaging and diffusion-weighted imaging

OBJECTIVES

Using gadoxetic acid-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI), the purpose of this study was to evaluate findings of focal hepatic eosinophilic infiltration.

METHODS

This retrospective study included 8 patients with 7 histologically confirmed focal eosinophilic infiltration (FEI) of the liver. One case was considered as FEI by using clinical findings and follow-up imaging. Gadoxetic acid-enhanced MRI and DWI were reviewed by 2 radiologists. We evaluated the signal intensity of focal lesions on T1-weighted, T2-weighted, and DW images and the pattern of enhancement in arterial, portal, equilibrium, and hepatobiliary phases of the gadoxetic acid-enhanced MRI. Apparent diffusion coefficient (ADC) value for focal eosinophilic infiltration was also calculated.

RESULTS

On T2-weighted images, 7 (88%) of 8 cases (7/8 lesions) showed mixed hyperintensity with irregular margins. Six (75%) of the 8 cases showed rim enhancement in the arterial phase. Most cases (5/8 lesions [63%]) showed isointensity or hypointensity in the portal and equilibrium phases. In the hepatobiliary phase, all cases (8/8) showed mixed hypointensity with irregular margins and nonspherical shapes. All cases showed hyperintensity in both low and high b-value ranges on DWI. The ADCs for 6 cases showed less than 1.05 × 10(-3) mm2/s (0.74 × 10(-3) to 1.03 × 10(-3) mm2/s).

CONCLUSIONS

Focal eosinophilic infiltration showed mixed hypointensity, irregular margins, and nonspherical shapes with excellent lesion-to-liver contrast in the hepatobiliary phase of the gadoxetic acid-enhanced MRI. Diffusion-weighted imaging and ADCs may not be helpful for characterizing these benign hepatic lesions.

MR findings of focal eosinophilic liver disease using gadoxetic acid

PURPOSE

The purpose of this study was to describe magnetic resonance (MR) findings of focal eosinophilic liver disease using gadoxetic acid (Gd-EOB-DTPA).

MATERIALS AND METHODS

Nineteen patients (M:F=14:5; age range, 26-66 years; mean age, 50 years) with 35 focal eosinophilic liver lesions were included after reviewing the medical records of 482 patients who underwent Gd-EOB-DTPA-enhanced MR imaging (MRI) on a 3.0-T unit between April 2008 and June 2009. The diagnosis of focal eosinophilic liver disease was established by means of percutaneous liver biopsy or surgery and consistent clinical findings. Two radiologists retrospectively reviewed MR images with consensus. Margin, shape and distribution of the lesions were analyzed. We also evaluated signal intensity of focal hepatic lesions on T(1)- and T(2)-weighted images and patterns of enhancement in dynamic contrast study.

RESULTS

The mean diameter of the lesions was 1.7 cm (range, 0.7-6.1 cm). Most of the focal eosinophilic liver lesions [n=31/35 (88.6%)] had poorly defined margins. They were usually isointense or slightly hypointense [n=34/35 (97.2%)] on T(1)-weighted images and hyperintense [n=32/35 (91.4%)] on T(2)-weighted images. Dynamic study showed enhancement (rim or homogeneous) on the arterial phase [n=21/35 (60%)] and hypointensity on the late venous phase [n=31/35 (88.6%)]. All the lesions were hypointense on the hepatobiliary phase images.

CONCLUSION

Focal eosinophilic liver lesions tend to be hyperintense on the arterial phase and hypointense on the late venous phase during dynamic study of Gd-EOB-DTPA-enhanced MRI. Although these findings mimic other focal hepatic lesions, poorly defined margins of the lesions and peripheral eosinophilia might help distinguish focal eosinophilic liver disease from other hepatic lesions.

Focal eosinophilic necrosis on superparamagnetic iron oxide-enhanced MRI

OBJECTIVE

The purpose of our study was to evaluate the usefulness of superparamagnetic iron oxide (SPIO)-enhanced MRI for distinguishing focal eosinophilic necrosis (FEN) from hepatic metastasis.

MATERIALS AND METHODS

Forty-one cases of FEN in 41 patients and 40 hepatic metastases in 40 patients were analyzed on unenhanced and SPIO-enhanced T2-weighted MRI retrospectively. Depending on the extent of the remaining hyperintense area on SPIO-enhanced T2-weighted images compared with the unenhanced images, the lesions were classified into four categories--category 1, less than 25%; category 2, 25-49%; category 3, 50-75%; and category 4, more than 75%--by two independent readers. Contrast-to-noise ratio (CNR) was measured using the same region of interest on unenhanced and SPIO-enhanced T2-weighted images. In three pathologic specimens of FEN, the number of Kupffer cells was compared with that of background hepatic parenchyma.

RESULTS

All metastases were classified as category 4, whereas FEN showed various distributions overall (category 1, 45.2%; category 2, 24.6%; category 3, 13.4%; category 4, 17.1%). FEN showed a decrease in CNR (from 7.9 +/- 5.8 to 6.1 +/- 5.6, p < 0.05), and metastases showed an increase in CNR (from 33.7 +/- 27.0 to 55.0 +/- 44.3, p < 0.05) after SPIO administration. In biopsy specimens, FEN had many more Kupffer cells (174.7 +/- 120.3 cells/high-power field [hpf]) than background hepatic parenchyma (23.7 +/- 9.8 cells/hpf). When using signal loss categories 1, 2, or 3 or CNR decrease, the accuracy of SPIO enhancement was 88.3%.

CONCLUSION

Unlike hepatic metastases, most of the cases of FEN showed a reduction in the extent of hyperintense area or a decrease in CNR after SPIO administration on the T2-weighted images. Therefore, SPIO-enhanced T2-weighted MRI can help to differentially diagnose FEN from metastases.

Hepatic Visceral Larva Migrans ofToxocara canis: CT and Sonographic Findings

OBJECTIVE

The aim of this study was to describe the CT and sonographic findings of hepatic visceral larva migrans of Toxocara canis.

MATERIALS AND METHODS

Fifty-four patients (44 men, 10 women; age range, 30-80 years; mean age, 53 years) with serologically confirmed visceral larva migrans of Toxocara canis underwent evaluation of the liver with CT (n = 25), sonography (n = 48), or both. Two radiologists used consensus for retrospective evaluation of CT and sonographic findings. Correlation between the presence and severity of hepatic abnormalities on images and the degree of peripheral eosinophilia was assessed.

RESULTS

Seventeen (68%) of 25 patients who underwent CT had single or multiple ill-defined, oval or elongated, small, low-attenuating lesions in the liver. Eighteen (38%) of 48 patients who underwent sonography had single or multiple small, poorly defined, oval or elongated, hypoechoic scattered focal lesions in the liver. In the 19 patients who underwent both CT and sonography, the two techniques had no significant difference in rate of detection of hepatic lesions (p = 0.375, McNemar test). The lesion numbers on CT and sonography showed excellent linear correlation (r = 0.844, p = 0.001) by Pearson's correlation test. An independent samples t test showed that eosinophil count and percentage in the peripheral blood were significantly higher in patients with hepatic lesions on CT and sonography than in patients without lesions.

CONCLUSION

CT and sonographic findings of hepatic visceral larva migrans of T. canis are multiple, ill-defined, oval or elongated, small, nodular lesions scattered in the liver parenchyma. The presence of hepatic lesions on images was associated with higher peripheral eosinophil count and percentage.

Contrast-enhancing hepatic eosinophilic abscess during the hepatic arterial phase: a mimic of hepatocellular carcinoma

OBJECTIVE

Our objective was to review CT, MR, angiographic, and sonographic images obtained in patients with histopathologically proven contrast-enhancing hepatic eosinophilic abscesses during the hepatic arterial phase.

CONCLUSION

On CT, MR, and angiographic images, eosinophilic abscess in the liver can show contrast enhancement during the hepatic arterial phase. If patients have peripheral hypereosinophilia or are at low risk for hepatocellular carcinoma or hepatic metastasis, those with small arterial-enhancing hepatic nodules need further preoperative evaluation, such as a sonographically guided biopsy.

Eosinophilic Hepatic Necrosis

OBJECTIVE

To compare the findings of magnetic resonance (MR) imaging with those of computed tomography (CT) of focal liver lesions related to peripheral eosinophilia.

METHODS

For 12 patients with peripheral eosinophilia (>7%) examined with hepatic MR imaging and CT, 52 focal hepatic lesions larger than 0.5 cm, including 31 lesions simultaneously found on the 2 imaging modalities, were subjected to a comparative analysis of their imaging features.

RESULTS

The total number of lesions distinguished from background liver was 39 (75%) on MR imaging and 44 (85%) on CT scans. On arterial phase images of 10 patients with comparable data, homogeneously hyperintense lesions were demonstrated more frequently (P = 0.006) on MR imaging (16 [50%] of 32 lesions) than on CT scans (4 [13%] of 32 lesions). Only 7 (22%) of the 32 hypoattenuating lesions on portal phase CT were depicted as hypointense lesions on portal phase MR images in 12 patients. On delayed phase images in 8 patients, the number of hyperintense lesions on MR images (9 [56%] of 16) was greater (P = 0.077) than that seen on the CT scans (4 [25%] of 16).

CONCLUSIONS

For many focal hepatic lesions related to peripheral eosinophilia, dynamic MR imaging more easily demonstrates lesional enhancement on arterial and delayed phases than CT scans. Because of the higher degree of lesional enhancement of MR imaging compared with CT, the lesion-to-liver contrast may not be sufficient to distinguish the lesion from the background liver, resulting in decreased sensitivity of portal phase dynamic MR imaging.

MRI Findings of Focal Eosinophilic Liver Diseases

OBJECTIVE

The purpose of this study was to describe the MRI findings of focal eosinophilic infiltration and eosinophilic abscess of the liver.

CONCLUSION

MRI shows characteristic findings of focal eosinophilic liver disease that can be helpful in differentiating lesions of focal eosinophilic liver disease from other focal liver lesions. In addition, eosinophilic abscess and focal eosinophilic infiltration showed different MRI findings from each other.

Focal Eosinophilic Necrosis Versus Metastasis in the Liver: The Usefulness of Two-Phase Dynamic CT

OBJECTIVE

The purpose of our study was to evaluate the usefulness of dual-phase dynamic CT in the differentiation of focal eosinophilic necrosis of the liver and metastasis.

CONCLUSION

Undetected isoattenuating lesions on arterial phase images that have an indistinct margin, a nonspherical shape, and a homogenous enhancement pattern on portal venous phase images suggest focal eosinophilic necrosis rather than metastasis. Two-phase dynamic CT was found to be useful at differentiating focal eosinophilic necrosis from metastasis.

MR Findings in Eosinophilic Infiltration of the Liver

OBJECTIVE

This study describes the findings of magnetic resonance imaging (MRI) of focal eosinophilic infiltration of the liver.

METHODS

Contrast-enhanced MR images of 8 patients with focal hepatic eosinophilic infiltration were reviewed retrospectively. We evaluated the signal intensity of focal lesions in T1-weighted and T2-weighted images and the pattern of enhancement in a dynamic contrast study.

RESULTS

A total 22 focal hepatic lesions were observed; the lesions were isointense (55%) or hypointense (45%) on T1-weighted images and isointense (14%) or hyperintense (86%) on T2-weighted images. The arterial phase of the contrast study revealed 11 hyperintense lesions (50%). During the portal and delayed phases, 18 (82%) and 17 lesions (77%) were hyperintense, respectively.

CONCLUSION

The focal eosinophilic infiltrations showed homogeneous enhancement in the portal and delayed phases in the dynamic contrast MR study. These findings should help to distinguish focal eosinophilic infiltration, especially from metastasis in patients with malignancy.