Fat replacement of the exocrine pancreas

Pathophysiological Mechanisms and Clinical Associations of Non-Alcoholic Fatty Pancreas Disease

Non-Alcoholic Fatty Pancreas disease (NAFPD), characterized by fat accumulation in pancreatic tissue, is an emerging clinical entity. However, the clinical associations, the underlying molecular drivers, and the pathophysiological mechanisms of NAFPD have not yet been characterized in detail. The NAFPD spectrum not only includes infiltration and accumulation of fat within and between pancreatic cells but also involves several inflammatory processes, dysregulation of physiological metabolic pathways, and hormonal defects. A deeper understanding of the underlying molecular mechanisms is key to correlate NAFPD with clinical entities including non-alcoholic fatty liver disease, metabolic syndrome, diabetes mellitus, atherosclerosis, as well as pancreatic cancer and pancreatitis. The aim of this review is to examine the pathophysiological mechanisms of NAFPD and to assess the possible causative/predictive risk factors of NAFPD-related clinical syndromes.

Fatty infiltration of the pancreas: a systematic concept analysis

Fatty infiltration of the pancreas (FIP) has been recognized for nearly a century, yet many aspects of this condition remain unclear. Regular literature reviews on the diagnosis, consequences, and management of FIP are crucial. This review article highlights the various disorders for which FIP has been established as a risk factor, including type 2 diabetes mellitus (T2DM), pancreatitis, pancreatic fistula (PF), metabolic syndrome (MS), polycystic ovary syndrome (PCOS), and pancreatic duct adenocarcinoma (PDAC), as well as the new investigation tools. Given the interdisciplinary nature of FIP research, a broad range of healthcare specialists are involved. This review article covers key aspects of FIP, including nomenclature and definition of pancreatic fat infiltration, history and epidemiology, etiology and pathophysiology, clinical presentation and diagnosis, clinical consequences, and treatment. This review is presented in a detailed narrative format for accessibility to clinicians and medical students.

Fatty Pancreas: Linking Pancreas Pathophysiology to Nonalcoholic Fatty Liver Disease

Currently, scientific interest has focused on fat accumulation outside of subcutaneous adipose tissue. As various imaging modalities are available to quantify fat accumulation in particular organs, fatty pancreas has become an important area of research over the last decade. The pancreas has an essential role in regulating glucose metabolism and insulin secretion by responding to changes in nutrients under various metabolic circumstances. Mounting evidence has revealed that fatty pancreas is linked to impaired β-cell function and affects insulin secretion with metabolic consequences of impaired glucose metabolism, type 2 diabetes, and metabolic syndrome. It has been shown that there is a connection between fatty pancreas and the presence and severity of nonalcoholic fatty liver disease (NAFLD), which has become the predominant cause of chronic liver disease worldwide. Therefore, it is necessary to better understand the pathogenic mechanisms of fat accumulation in the pancreas and its relationship with NAFLD. This review summarizes the epidemiology, diagnosis, risk factors, and metabolic consequences of fatty pancreas and discusses its pathophysiology links to NAFLD.

Pancreatic Steatosis Is Associated with Both Metabolic Syndrome and Pancreatic Stiffness Detected by Ultrasound Elastography

INTRODUCTION

There is increasing evidence that pancreatic steatosis (PS) is associated with metabolic syndrome (MS). However, it is not known whether it is associated with PS grade and pancreatic stiffness, or not. We aimed to evaluate the relationship between PS and its grade detected by transabdominal ultrasound, and pancreatic stiffness determined by two-dimensional shearwave elastography (2D-SWE), whether it has clinical significance and its relationship with MS.

METHODS

Patients with and without PS were evaluated prospectively.

RESULTS

Patients with PS had higher odds ratio for MS (OR 5.49). Also, ultrasonographic grade of PS was associated with MS parameters and hepatosteatosis. Pancreatic SWE value was significantly higher in PS group and positively correlated with PS grade, liver fat, MS, number of MS criteria.

DISCUSSION/CONCLUSION

PS and its grade were associated with MS. In this first comprehensive PS-SWE study, we found that pancreas stiffness increased in the presence of PS, in correlation with PS grade and MS.

Metabolic implications of pancreatic fat accumulation

Fat accumulation outside subcutaneous adipose tissue often has unfavourable effects on systemic metabolism. In addition to non-alcoholic fatty liver disease, which has received considerable attention, pancreatic fat has become an important area of research throughout the past 10 years. While a number of diagnostic approaches are available to quantify pancreatic fat, multi-echo Dixon MRI is currently the most developed method. Initial studies have shown associations between pancreatic fat and the metabolic syndrome, impaired glucose metabolism and type 2 diabetes mellitus. Pancreatic fat is linked to reduced insulin secretion, at least under specific circumstances such as prediabetes, low BMI and increased genetic risk of type 2 diabetes mellitus. This Review summarizes the possible causes and metabolic consequences of pancreatic fat accumulation. In addition, potential therapeutic approaches for addressing pancreatic fat accumulation are discussed.

Pancreatic steatosis: A frequent finding in a Chilean population

INTRODUCTION AND AIMS

Pancreatic steatosis is an incidental radiologic finding in asymptomatic patients, and its clinical importance is unclear. Primary aim: to study the prevalence of pancreatic steatosis (PS) in consecutive patients registered at our hospital, that underwent computed axial tomography (CAT) scanning of the abdomen and pelvis, excluding known pancreatic diseases. Secondary aim: to review the association of PS with the demographic and clinical data of the patients, as well as with hepatic steatosis (HS).

MATERIALS AND METHODS

An observational study was conducted on adult patients that had CAT scans of the abdomen and pelvis.

DEFINITIONS

a) tissue density was measured in Hounsfield units (HU) in five 1 cm² areas of the pancreas, three areas of the spleen, and in segments VI and VII of the liver; b) fatty pancreas: a difference < -10 HU between the mean pancreas and mean spleen densities; and c) fatty liver: density < 40 HU. We registered the epidemiologic and laboratory data of the patients. The association of those factors with the presence of PS was analyzed using SPSS version 24.0 software, and statistical significance was set at a p < 0.05.

RESULTS

Of the 203 patients, PS was found in 61 (30%). The patients with PS were significantly older and had a higher body mass index. We found no significant association with the rest of the parameters studied, nor with HS (55 patients). None of the patients had symptoms attributable to a disease of the exocrine pancreas.

CONCLUSIONS

Fatty infiltration of the pancreas is a frequent finding in CAT scans, and its clinical importance is unclear. Aging of the population and the increase in obesity underline the need for future studies on PS.

Determining age and sex-specific distribution of pancreatic whole-gland CT attenuation using artificial intelligence aided image segmentation: Associations with body composition and pancreatic cancer risk

BACKGROUND & AIMS

Increased intrapancreatic fat is associated with pancreatic diseases; however, there are no established objective diagnostic criteria for fatty pancreas. On non-contrast computed tomography (CT), adipose tissue shows negative Hounsfield Unit (HU) attenuations (-150 to -30 HU). Using whole organ segmentation on non-contrast CT, we aimed to describe whole gland pancreatic attenuation and establish 5th and 10th percentile thresholds across a spectrum of age and sex. Subsequently, we aimed to evaluate the association between low pancreatic HU and risk of pancreatic ductal adenocarcinoma (PDAC).

METHODS

The whole pancreas was segmented in 19,456 images from 469 non-contrast CT scans. A convolutional neural network was trained to assist pancreas segmentation. Mean pancreatic HU, volume, and body composition metrics were calculated. The lower 5th and 10th percentile for mean pancreatic HU were identified, examining the association with age and sex. Pre-diagnostic CT scans from patients who later developed PDAC were compared to cancer-free controls.

RESULTS

Less than 5th percentile mean pancreatic HU was significantly associated with increase in BMI (OR 1.07; 1.03-1.11), visceral fat (OR 1.37; 1.15-1.64), total abdominal fat (OR 1.12; 1.03-1.22), and diabetes mellitus type 1 (OR 6.76; 1.68-27.28). Compared to controls, pre-diagnostic scans in PDAC cases had lower mean whole gland pancreatic HU (-0.2 vs 7.8, p = 0.026).

CONCLUSION

In this study, we report age and sex-specific distribution of pancreatic whole-gland CT attenuation. Compared to controls, mean whole gland pancreatic HU is significantly lower in the pre-diagnostic phase of PDAC.

Nonalcoholic fatty pancreas disease: An emerging clinical challenge

Nonalcoholic fatty pancreas disease (NAFPD) is an emerging disease that has gained an increasing amount of attention in recent years. It describes fat accumulation in the pancreas with insignificant alcohol consumption, but the pathogenesis is largely unknown. A wide range of terms have been used to describe the phenomenon of pancreatic fat accumulation, but NAFPD remains an under-recognized and non-independent disorder. Obesity, age, sex, race, and unhealthy lifestyle are established independent risk factors for NAFPD, which is strongly associated with metabolic syndrome, type 2 diabetes, pancreatitis, pancreatic fistula, pancreatic cancer, and nonalcoholic fatty liver disease. At present, imaging techniques are common diagnostic aids, but uniform criteria and consensus are lacking. Therapeutically, healthy diet, weight loss, and exercise are the mainstays to reduce pancreatic fat accumulation. It can be seen that there is a limited understanding of NAFPD at this stage and further exploration is needed. Previous studies have revealed that NAFPD may directly affect diagnosis and clinical decision-making. Therefore, exploring the pathophysiological mechanism and clinical associations of NAFPD is a major challenge for researchers and clinicians.

The relation of CT quantified pancreatic fat index with visceral adiposity and hepatic steatosis

Objectives

The purpose of this study was to investigate the relation between pancreatic steatosis and visceral adiposity. Furthermore, the study sought to explore the association between pancreatic steatosis, pancreas volume, hepatic steatosis, age, and sex in adults without prior history of pancreatic disease. The research also served to define a cut-off value of visceral fat tissue area (VFA) predicting fatty pancreas.

Material and Methods

CT scans of 98 living-liver donor transplant patients without prior history of pancreatic disease were evaluated for the presence of fatty pancreas. Pancreas volume, VFA, subcutaneous-total FA, VFA/TFA ratios of the patients with and without fatty pancreas were quantified with a semi-automated model on CT. Coexistence of hepatic steatosis was also recorded.

Results

VFA, TFA and VFA/TFA were significantly greater in the fatty group (p<0.001, p<0.001, p<0.001; respectively), and pancreatic steatosis was moderately correlated with VFA, VFA/TFA and TFA with the highest correlation coefficient with VFA (r=-0.715, r=-0.605, r=-0.573, respectively; p<0.001 for all). A cut-off value of VFA ≥ 107.2 cm2 estimates pancreatic steatosis with a sensitivity and specificity of 90% (95% CI=77-96%) and 87.9% (95% CI=77%-94%), respectively. Pancreas volume was higher in the fatty-group with a mean value of 86.5±17.3 mL (range; 58-119.2 mL, p=0.097). In multiple logistic regression analyses, pancreatic steatosis was significantly associated with VFA and the male sex (OR=58.2, 95% CI=12.2-277.1, p<0.001; OR=11.4, 95% CI=2.1-63.4, p<0.001; respectively). 77.5% of the fatty pancreas subjects had co-existing hepatic steatosis.

Conclusion

Pancreatic steatosis is related to higher VFA, VFA/TFA and hepatic steatosis. A cut-off value of VFA ≥ 107.2 cm² may predict pancreatic steatosis.

Pancreatic Steatosis: An Emerging Clinical Entity

Pancreatic steatosis is an emerging clinical entity whose pathophysiology, natural history, and long-term complications are poorly characterized in the current literature. Epidemiological and prospective studies have described prevalence rates between 16% and 35%. Although the natural history is not well known, there are strong associations with obesity, metabolic syndrome, type 2 diabetes mellitus, and nonalcoholic fatty liver disease. Ectopic fat accumulation of the pancreas can cause chronic, low-grade inflammation from adipocytokine imbalances that involve beta cells and acinar cells. This mechanism can lead to pancreatic endocrine and exocrine dysfunction and initiate carcinogenesis. Although it is associated with morbid conditions, pancreatic steatosis may be amendable to treatment with a healthy diet, less meat consumption, exercise, and smoking cessation. Pancreatic steatosis should factor into clinical decision-making and prognostication of patients with pancreatic and systemic disease. This review seeks to describe the pathophysiology, natural history, diagnosis, and complications of this emerging clinically relevant entity.

Pancreatic steatosis: an update

PURPOSE OF REVIEW

Pancreatic steatosis is a clinical entity with emerging significance and impacts patient health in a multitude of ways. It has a high prevalence in the global population with predilections for different demographics by age, sex and ethnicity. Understanding the pathophysiology, clinical features and complications of this entity may be important to understanding the consequences of the ongoing obesity global epidemic.

RECENT FINDINGS

Obesity and metabolic syndrome contribute to metabolic derangements that result in lipid mishandling by adipocytes. Adipocytokine imbalances in circulation and in the pancreatic microenvironment cause chronic, low-grade inflammation. The resulting beta cell and acinar cell apoptosis leads to pancreatic endocrine and exocrine dysfunction. Furthermore, these adipocytokines regulate cell growth, differentiation, as well as angiogenesis and lymphatic spread. These consequences of adipocyte infiltration are thought to initiate carcinogenesis, leading to pancreatic intraepithelial neoplasia and pancreatic ductal adenocarcinoma.

SUMMARY

Obesity will lead to millions of deaths each year and pancreatic steatosis may be the key intermediate entity that leads to obesity-related complications. Enhancing our understanding may reveal strategies for preventing mortality and morbidity related to the global epidemic of obesity. Further research is needed to determine the pathophysiology, long-term complications and effective treatment strategies for this condition.

Effects of aging and menopause on pancreatic fat fraction in healthy women population: A strobe-compliant article

Pancreatic fat fraction has been shown to increase in many pathological situations. However, pancreatic fat fraction and its physiological changes in healthy women are still unclear. The aim of this study is to investigate the effect of aging and menopause on pancreatic fat fraction in healthy female population.This was a cross-sectional study. A phantom of fat-water mixtures was established. One hundred sixty-seven healthy women (20-70 years) were recruited. Fat fraction was quantified with double-echo chemical shift magnetic resonance imaging with T1 and T2* correction. The association between measured and actual fat fractions was determined with Pearson correlation. Linear regression analysis was used to establish the calibration curve. Fat fractions were analyzed via analysis of variance.A significant positive linear correlation was revealed between the measured and actual fat fractions on the phantom (r = 0.991, P < .001). There was no significant difference in fat fractions among caput, corpus, and cauda of the pancreas. Pancreatic fat fraction remained constant during the age of 20 to 40 years (4.41 ± 0.79%) but significantly increased during the ages of 41 to 50 and 51 to 70 years (7.49 ± 1.10% and 9.43 ± 1.51%, respectively, P < .001). Moreover, pancreatic fat fractions of the healthy women aged 41 to 70 years were still significantly higher than these in the groups aged 20 to 40 years when postmenopausal healthy women were removed (P < .001). For volunteers aged 46 to 49 years, pancreatic fat fraction of the postmenopausal women was significantly increased compared with that of their premenopausal counterparts (P < .001).We found that an even distribution of pancreatic fat in healthy women, aging and menopause as 2 independent risk factors for pancreatic steatosis, a fatty infiltration in the pancreas beginning in the fifth decade in women.

Fatty Pancreas: Should We Be Concerned?

The metabolic consequences of visceral fat deposition are well known, and the presence of intrapancreatic fat (IPF) has been recognized for decades. However, our knowledge about the distribution of fat in the pancreas and its clinical implications is in a nascent stage. Various terms have been proposed to describe IPF; for the purpose of this narrative review, we chose the general term fatty pancreas. Herein, we describe the radiologic, endoscopic, and histopathologic aspects of diagnosing fatty pancreas and provide an overview of the diseases associated with this condition. Our purpose is to highlight diagnostic challenges and identify specific clinical questions that would benefit from further study. As evident in this review, IPF is associated with various metabolic diseases, pancreatitis, pancreatic cancer, and precancer-yet establishing causality needs careful, further study.

Exploring the metabolic syndrome: Nonalcoholic fatty pancreas disease

After the first description of fatty pancreas in 1933, the effects of pancreatic steatosis have been poorly investigated, compared with that of the liver. However, the interest of research is increasing. Fat accumulation, associated with obesity and the metabolic syndrome (MetS), has been defined as “fatty infiltration” or “nonalcoholic fatty pancreas disease” (NAFPD). The term “fatty replacement” describes a distinct phenomenon characterized by death of acinar cells and replacement by adipose tissue. Risk factors for developing NAFPD include obesity, increasing age, male sex, hypertension, dyslipidemia, alcohol and hyperferritinemia. Increasing evidence support the role of pancreatic fat in the development of type 2 diabetes mellitus, MetS, atherosclerosis, severe acute pancreatitis and even pancreatic cancer. Evidence exists that fatty pancreas could be used as the initial indicator of “ectopic fat deposition”, which is a key element of nonalcoholic fatty liver disease and/or MetS. Moreover, in patients with fatty pancreas, pancreaticoduodenectomy is associated with an increased risk of intraoperative blood loss and post-operative pancreatic fistula.

Pancreatic Lipomatosis: An Extensive Pictorial Review

Pancreatic lipomatosis – also commonly called fat replacement – represents the most frequent benign pathologic condition of the adult pancreas. Most cases remain asymptomatic, and only some rare extreme degrees of lipomatosis or fat replacement may lead to exocrine pancreatic insufficiency.

The precise etiology of the entity remains unclear, and the condition has been found associated with several diseases comprising diabetes mellitus, metabolic syndrome, acquired or hereditary pancreatitis, alcoholic hepatitis, cystic fibrosis and condition comprising increasing age, body mass index, or more precisely visceral fat index, and use of steroid therapy. Numerous cases are also associated with condition compromising the permeability of the pancreas ductal system, such as intraductal calculus, pancreatic tumors, and congenital or experimental stenosis.

Uneven lipomatosis and fat replacement are also common presentations and responsible for the great diversity of imaging features. The reasons for uneven presentations are controversial and probably interweave embryologic or ductal hypotheses. Lipomatous pseudohypertrophy of the pancreas represents the most extreme situation of pancreatic lipomatosis and is considered, probably in a contestable way, as a rare, specific, and distinct entity.

We hereby present an extensive pictorial review of the broad spectrum of imaging features of this entity. The images are extracted from a compilation of cases collected in our department over more than a decade. We review and discuss the embryologic and ductal hypothesis, the differential diagnosis. Finally, we illustrate some unusual presentations and evolutions.

Alcohol and high fat induced chronic pancreatitis: TRPV4 antagonist reduces hypersensitivity

The pathogenesis of pain in chronic pancreatitis is poorly understood, and its treatment can be a major clinical challenge. Surgical and other invasive methods have variable outcomes that can be unsatisfactory. Therefore, there is a great need for further discovery of the pathogenesis of pancreatitis pain and new therapeutic targets. Human and animal studies indicate a critical role for oxidative stress and activation of transient receptor potential (TRP) cation channel subfamily members TRPV1 and TRPA1 on pancreatic nociceptors in sensitization mechanisms that result in pain. However, the in vivo role of transient receptor potential cation channel subfamily V member 4 (TRPV4) in chronic pancreatitis needs further evaluation. The present study characterized a rat alcohol/high fat diet (AHF)-induced chronic pancreatitis model with hypersensitivity, fibrotic pathology, and fat vacuolization consistent with the clinical syndrome. The rats with AHF-induced pancreatitis develop referred visceral pain-like behaviors, i.e. decreased hindpaw mechanical thresholds and shortened abdominal and hindpaw withdrawal latency to heat. In this study, oxidative stress was characterized as well as the role of TRPV4 in chronic visceral hypersensitivity. Lipid peroxidase and oxidative stress were indicated by increased plasma thiobarbituric acid reactive substances (TBARS) and diminished pancreatic manganese superoxide dismutase (MnSOD). The secondary sensitization associated with AHF-induced pancreatitis was effectively alleviated by the TRPV4 antagonist, HC 067047. Similarity of the results to those with the peripherally restricted μ-opiate receptor agonist, loperamide, suggested TRPV4 channel activated peripheral sensitization. This study using a reliable model that provides pre-clinical correlates of human chronic pancreatitis provides further evidence that TRPV4 channel is a potential therapeutic target for treatment of pancreatitis pain.

Selective fatty replacement of the exocrine pancreas in a domestic shorthair cat: histopathological findings with long-term outcome

The clinical, histopathological findings and eventual outcome of a cat with marked and selective fatty replacement of the exocrine pancreas are described in this case report. A 9-year-old female neutered domestic shorthair cat presenting with polyphagia, weight loss and intermittent vomiting was diagnosed on histopathology with severe exocrine pancreatic atrophy, with relative sparing of the endocrine pancreas and replacement of the acinar cells by mature adipose tissue. This case report discusses the histological findings in this case and the eventual outcome, as well as the potential underlying causes of this histological change.

Does the visceral fat tissue show better correlation with the fatty replacement of the pancreas than with BMI?

OBJECTIVE

Obesity is a risk factor of fatty replacement of the pancreas. We aimed to investigate whether there is a better correlation between the visceral fat tissue and the fatty infiltration of the pancreas than with the BMI.

MATERIALS AND METHODS

One hundred-eighteen patients were visually divided into three groups according to the pattern of the fatty infiltration of the pancreas. Group 0 (n=70) has no fatty infiltration, Group 1 (n=23) has fatty infiltration on the head only, and Group 2 (n=25) has fatty infiltration on the entire pancreas. Additionally, the attenuation numbers (HU) were measured separately at the head, body and tail of the pancreas on contrast-enhanced Computed Tomography CT. The sum of the attenuation number of each part of the pancreas was calculated as the attenuation number of the pancreas. A CT-scan was used to calculate the visceral fat area (cm(2)). Correlation coefficients were determined between the visceral fat area and fatty infiltration of the pancreas and the BMI.

RESULTS

The visceral fat area showed a stronger correlation with the attenuation number of the pancreas than the BMI (r=-0.552, r=-0.345 and p=0.0001, p=0.0001, respectively). The difference existed between the Groups 0 and 1 (p=0.0001) or Groups 0 and 2 (p=0.0001) in terms of visceral fat area. The difference existed only between Group 0 and Group 2 in terms of BMI (p=0.006).

CONCLUSIONS

The visceral fat tissue area has a stronger correlation than the BMI in the fatty infiltration of the pancreas.

Atypically large well-differentiated hepatocellular carcinoma with extensive fatty metamorphosis: report of a case

A large well-differentiated hepatocellular carcinoma (HCC) with fatty change is rare, and to date only a few cases have been reported. Herein, we present a 68-year-old man who developed a well-differentiated HCC with extensive fatty metamorphosis. The patient was referred to our institute because of a rapidly growing tumor in the left lobe of the liver. Ultrasonography showed a hyperechoic lesion with a peripheral hypoechoic area. Dynamic contrast-enhanced computed tomography (CT) scan in all three phases revealed the tumor which showed diffuse low attenuation with internal irregular enhancement. He underwent left lateral segmentectomy at the liver. Histological diagnosis confirmed well-differentiated HCC and the surrounding non-cancerous area was diagnosed as non-alcoholic steatohepatitis. The patient is still alive without recurrence after 17 months of follow-up.

Imaging of miscellaneous pancreatic pathology (trauma, transplant, infections, and deposition)

In this article's coverage of miscellaneous pancreatic topics, a brief review of pancreatic trauma; pancreatic transplantation; rare infections, such as tuberculosis; deposition disorders, including fatty replacement and hemochromatosis; cystic fibrosis; and others are discussed with pertinent case examples.

Congenital pancreatic anomalies, variants, and conditions

Understanding pancreatic development and the congenital anomalies and variants that result from alterations in normal development allows for better recognition of these anomalies at diagnostic imaging. This article reviews normal pancreatic embryology and anatomy, and the appearance of the more common developmental anomalies and ductal variants, with emphasis on computed tomography and magnetic resonance imaging. Common mimics of masses are also covered.

The clinical significance of pancreatic steatosis

More research is now focused on pancreatic steatosis. Multiple definitions, clinical associations and synonyms for pancreatic steatosis are described in the literature and can be confusing. The integration and comparison of several studies concerning this topic is therefore challenging. In the past, pancreatic steatosis was considered an innocuous condition, a bystander of many underlying diseases (such as congenital syndromes, hemochromatosis and viral infection). However, evidence that pancreatic steatosis (strongly associated with obesity and the metabolic syndrome) has a role in type 2 diabetes mellitus, pancreatic exocrine dysfunction, acute pancreatitis, pancreatic cancer and the formation of pancreatic fistula after pancreatic surgery is emerging. This Review focuses on the different etiological factors and the clinical consequences of pancreatic steatosis.

Total pancreatic lipomatosis with malabsorption syndrome

Total fat replacement of the pancreas is rare. Focal fatty replacement is the most common degenerative lesion of pancreas. Focal fatty deposits have no major clinical significance; however, extreme fat replacement is of pathologic significance, as it is associated with marked reduction in exocrine function of pancreas, resulting in malabsorption due to pancreatic enzyme insufficiency.

Total replacement of the exocrine pancreas with fat following multiple blunt injuries

We describe an unusual case of total replacement of the exocrine pancreas with fat, which was observed in an autopsy of an assaulted victim. A woman in her early 80s was kicked, stamped and hit several times with firewood. She was hospitalized with disturbance of consciousness, left haemothorax and multiple fractures, and died about three months later. Postmortem examination revealed extensive abrasions and bruises, multiple fractures and internal organ injuries such as contusion and haemorrhage, as well as bronchopneumonia. It was concluded that the cause of her death was hypostatic pneumonia followed by traumatic shock due to multiple blunt injuries. Further, complete replacement of the pancreas with fat was observed in addition to a calculus in the main pancreatic duct and fibrous hypertrophy of the ductal wall. Histopathological examination revealed almost complete replacement of the pancreatic acini by fat tissue, whereas the islets of Langerhans were mostly intact. Antemortem laboratory data showed that serum amylase levels were almost within normal range before hospital admission, but underwent a transient abnormal elevation at admission followed by extremely low levels thereafter. Previous reports suggest that obstruction of both the main pancreatic duct and the artery, due to tumour formation or calculus in combination with arteriolar sclerosis, are necessary to induce total replacement of the pancreas with fat. Since arteriolar sclerosis was not remarkable in this case, we speculated that pancreatic ischaemia due to circulatory disturbance caused by traumatic shock, in combination with pre-existing calculus, may have contributed to the development of total replacement with fat. The temporal alterations in serum amylase levels support our speculation. There are few, if any, reports regarding organ replacement with fat in association with trauma. This case suggests that multiple injuries followed by traumatic shock may advance pre-existing replacement of the pancreas with fat.

Sonographic appearance of focal fatty infiltration of the pancreas

We report the sonographic, CT, and MRI findings in a case of focal fatty infiltration of the pancreas. Sonography revealed an echogenic mass in pancreas head. On CT, the mass was hypodense. The mass showed same signal intensity to the surrounding normal pancreas on in-phase T1-weighted MR images and a loss of signal intensity on opposed-phase MR images.

Rosiglitazone aggravates nonalcoholic Fatty pancreatic disease in C57BL/6 mice fed high-fat and high-sucrose diet

OBJECTIVES

Evaluate the effect of fenofibrate, bezafibrate, and rosiglitazone on nonalcoholic fatty pancreatic disease and islet peroxisome proliferator-activated receptor-alpha (PPAR-alpha) and PPAR-beta immunostain in mice fed high-fat high-sucrose (HFHS) diet.

METHODS

Two-month-old male mice were fed standard chow (n = 10) or HFHS chow (n = 40) for 6 weeks. Afterward, HFHS mice were grouped by treatment: untreated HFHS and HFHS treated with rosiglitazone (HFHS-Ro), fenofibrate (HFHS-Fe), or bezafibrate (HFHS-Bz). Medications were administered for 5 weeks. After treatment, the pancreas was removed and analyzed by morphometry, stereology, and immunohistochemistry.

RESULTS

The HFHS-fed mice showed altered fasting glucose (+33%) and insulin (+138%); increased body (+20%) and pancreas (+28%) masses, pancreatic fat (+700%), islet hypertrophy (+38%); and decreased GLUT2 immunostain (-60%). Rosiglitazone reduced fasting glucose and insulin but induced weight gain. Fibrates impeded weight gain, but only bezafibrate prevented islet hypertrophy. The GLUT2 stain was improved in all treatments, and there were no alterations in PPAR-alpha. There were morphological signs of pancreatitis with fenofibrate, although there were no alterations in amylase and lipase. Rosiglitazone exacerbated pancreatic fat infiltration (+75% vs HFHS group), and bezafibrate increased PPAR-beta expression in pancreatic islets.

CONCLUSIONS

Rosiglitazone is shown for the first time to exacerbate pancreatic fat infiltration; therefore, precaution has to be taken when rosiglitazone is prescribed to obese patients.

Focal fatty infiltration in the head of the pancreas: evaluation with multidetector computed tomography with multiplanar reformation imaging

Fatty infiltration of the pancreas is generally a diffuse process; however, it may be unevenly distributed in the pancreas. Focal fatty infiltration of the pancreas is usually most prominent in the anterior aspect of the head of the pancreas and seen as a region of decreased attenuation on computed tomography and may simulate pancreatic neoplasm. We discuss and illustrate the various features of focal fatty infiltration of the pancreas on multidetector row helical computed tomography with multiplanar reformation images and show how this imaging modality helps to differentiate between focal fatty infiltration of the pancreas and actual pancreatic tumors.

[Diffuse primary fat replacement of the pancreas: an unusual cause of steatorrhea]

Diffuse and primitive fat replacement of the exocrine pancreas is a rare cause of exocrine pancreatic insufficiency in adults. We report two adult patients with chronic diarrhoea and steatorrhea whose morphologic abnormalities revealed diffuse fat replacement of the pancreas. Tomodensitometry detected diffuse characteristic abnormalities with fat intermixed with normal pancreatic lobules or a "vanishing pancreas". In one patient, magnetic resonance imaging and echo-endoscopy suggested abnormalities. Administration of pancreatic extracts improved symptoms.

Focal fatty replacement of the pancreas: usefulness of chemical shift MRI

OBJECTIVE

The purpose of this study was to describe the typical CT and chemical shift MRI findings and to evaluate their usefulness in the diagnosis of focal fatty replacement of the pancreas in five patients.

CONCLUSION

The presence of a perceptible focal low-attenuation lesion in the pancreas on CT and the reduction in signal intensity of the lesion on the opposed phase of chemical shift MR images are useful for differentiating focal fatty replacement of the pancreas from true pancreatic neoplasm. Therefore, these imaging findings obviate invasive diagnostic procedures and surgery in the care of patients with focal fatty replacement of the pancreas.

CT differentiation of distal pancreas fat replacement and distal pancreas agenesis

We aimed to describe CT signs useful for differentiation of distal agenesis from distal or dorsal pancreas lipomatosis. Multidetector CT (MDCT) studies of five patients with distal pancreas agenesis (n = 2), distal lipomatosis (n = 1), distal short pancreas (n = 1), and distal pancreatectomy (n = 1) were retrospectively reviewed. Agenesis of dorsal pancreas can be diagnosed by the absence of body and tail of pancreas. In the absence of distal pancreas, distal pancreatic bed can be filled by stomach or intestine (dependent stomach or dependent intestine signs), which abut splenic vein. Same findings can be seen in patients with distal pancreatectomy, however, splenic vein is absent in these patients. In case of distal lipomatosis abundant fat tissue is observed anterior to splenic vein. Dependent stomach and/or dependent intestine signs on MDCT imaging can allow differentiation of distal pancreas agenesis from distal lipomatosis obviating further diagnostic studies.

Insulinoma occurring in association with fatty replacement of unknown etiology in the pancreas: report of a case

A 66-year-old woman with a 10-year-history of diabetes mellitus was admitted to our hospital for investigation of several recent attacks of hypoglycemia. Her fasting blood glucose level was very low, at 30-40 mg/dl, and abdominal ultrasonography and computed tomography revealed a tumor in the pancreatic tail with fatty changes. Endoscopic retrograde cholangiopancreatography revealed absence of the main pancreatic duct from the body to tail of the pancreas. Abdominal angiography showed a hypervascular tumor stain in the pancreas, and percutaneous transhepatic portal vein sampling demonstrated a step-up of immunoreactive insulin levels in the splenic vein. Based on these clinical findings, we made a preoperative diagnosis of an insulinoma accompanied by fatty changes in the pancreatic body and tail. During laparotomy for the insulinoma, fat tissue was identified in the anatomic location of the pancreatic body and tail, and resected. Pathological examination of the resected specimen revealed a number of Langerhans islets in the adipose tissue, and an islet cell tumor with fatty replacement of the pancreatic tissue around the tumor. The insulinoma was found not to have caused obstruction of the main pancreatic duct. We present herein a rare case of an insulinoma that developed in the pancreas, and was associated with fatty replacement of unknown etiology.

Fat replacement with absence of acinar and ductal structure in the pancreatic body and tail

We report an unusual case of fat replacement of the pancreatic body and tail. Findings on contrast-enhanced computed tomography and ERCP could be confused with dorsal pancreas agenesis. Histopathologic examination of the resected specimen revealed massive fat replacement with complete absence of the acinar and ductal tissue and scattered islets of Langerhans.

Cystic fibrosis in adolescents and adults: fatty replacement of the pancreas--CT evaluation and functional correlation

PURPOSE

To compare the computed tomographic (CT) features of pancreatic fatty replacement in adolescents and adults with cystic fibrosis (CF) with those in control subjects and to correlate the degree of fatty replacement with the functional status of the pancreas.

MATERIALS AND METHODS

CT scans in 15 patients with CF (group 1) and in 15 control subjects without CF (group 2) were evaluated for thickness and degree of pancreatic fatty replacement. Thickness was measured at four anatomic levels. The pattern of pancreatic fatty replacement was visually evaluated in four pancreatic regions. Images were semiquantitatively analyzed by two readers. The degree of fatty replacement was correlated with the functional status of the pancreas.

RESULTS

In group 1, pancreatic glandular tissue was significantly thinner (P < .001) and the degree of fatty replacement was significantly greater in the four regions (P < .001) than those in group 2. In Group 1, no relationship was found between the degree of pancreatic fatty replacement and that of pancreatic endocrine dysfunction. A significant relationship was found between the degree of fatty replacement and that of pancreatic exocrine dysfunction (P < .001).

CONCLUSION

In patients with CF, pancreatic glandular tissue is significantly reduced in size. Pancreatic fatty replacement is the most frequent pattern in older patients with CF and correlates with pancreatic exocrine dysfunction.

Fatty replacement of the pancreatic body and tail associated with leiomyosarcoma of the pancreatic head

A case of fatty replacement of the pancreatic body and tail associated with leiomyosarcoma of the pancreatic head is presented. Clinicopathological features as well as differential diagnoses are described with a review of the literature on both leiomyosarcoma and fatty replacement of the pancreas. A possible correlation between the two lesions is also discussed.

Agenesis and pseudo-agenesis of the dorsal pancreas

Agenesis of the dorsal pancreatic anlage is a very unusual congenital anomaly. The case reported appears to be accompanied by hypertrophy of the ventral gland. Atrophy of the pancreas following an episode of acute pancreatitis is also very unusual. When the atrophy spares the uncinate process, it may also resemble agenesis of the dorsal gland.

Transfusional hemosiderosis in sickle cell anemia: another cause of an echogenic pancreas

We report four sickle cell anemia patients who have received multiple blood transfusions and have been non-compliant on Desferal chelation therapy. Abdominal ultrasonography demonstrated an echogenic pancreas in all four patients. Magnetic resonance imaging in three patients revealed decreased signal intensity in all sequences in the pancreas and liver. All four patients had marked iron deposition on liver biopsy. To our knowledge, increased echogenicity of the pancreas secondary to hemosiderosis (2 degrees hemochromatosis) in sickle cell patients has not been reported in the radiologic literature.

Pancreatic lipomatosis in the Shwachman-Diamond syndrome. Identification by sonography and CT-scan

The typical pathological finding in the pancreas of patients with the Shwachman-Diamond syndrome is fatty infiltration. In this report it is emphasized that this lipomatosis can be demonstrated by non-invasive techniques, using abdominal ultrasound and CT-scan.

Fatty infiltration of the peripancreatic space: CT confirmation of a normal variant

Widening of the duodenal sweep on upper GI series is a sign of mass in the pancreatic head. A series of patients was examined in which the widening of the duodenal sweep was solely due to fatty infiltration of the peripancreatic space. Because CT established the diagnosis, more invasive procedures were obviated.