Autoimmune pancreatitis: CT and MR characteristics

Autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is a benign, IgG4-related, fibroinflammatory form of chronic pancreatitis that can mimic pancreatic ductal adenocarcinoma both clinically and radiographically. Laboratory studies typically demonstrate elevated serum IgG4 levels and imaging studies reveal a diffusely or focally enlarged pancreas with associated diffuse or focal narrowing of the pancreatic duct. The pathologic features include periductal lymphoplasmacytic inflammation, obliterative phlebitis, and abundant IgG4-positive plasma cells. The treatment of choice for AIP is steroid therapy. Diagnostic criteria for AIP have been proposed that incorporate histologic, radiographic, serologic, and clinical information.

Autoimmune pancreatitis with multifocal mass lesions

Autoimmune pancreatitis (AIP) is radiologically characterized as diffuse swelling of the pancreatic parenchyma and irregular narrowing of the pancreatic ducts. We present a case of AIP with multiple small nodular lesions in the pancreas. This case suggests that AIP with only small nodular or localized lesions is more difficult to differentiate from pancreatic cancer than typical cases of AIP.

Diagnostic criteria for autoimmune chronic pancreatitis

Autoimmune chronic pancreatitis (AIP) is a clinically attractive entity because of its dramatic response to oral steroid therapy. Recently, as awareness of AIP is increasing, more cases are being reported. However, there are still no established worldwide diagnostic criteria for AIP. Since the Japan Pancreas Society (JPS) published diagnostic criteria for autoimmune chronic pancreatitis in the year 2002, increased attention toward this relatively new disease entity has enabled more cases of AIP to be correctly diagnosed. As previously unrecognized or misdiagnosed cases of autoimmune chronic pancreatitis are found, an increasing number of cases that are not in full accordance with the JPS diagnostic criteria are revealed. As a result, some groups have developed and cited their own criteria in the reporting of autoimmune chronic pancreatitis. The absence of consistent, uniform criteria has made comparison of different cases diagnosed under various guidelines difficult. In this review, we discuss and compare the four current sets of diagnostic criteria, focusing on their individual strengths and weaknesses.

Diagnosis of autoimmune pancreatitis using its five cardinal features: introducing the Mayo Clinic's HISORt criteria

Autoimmune pancreatitis (AIP) is a recently defined form of chronic pancreatitis. While numerous case reports and small case series of AIP have been reported from Japan, there have been relatively few from the West. Based on a retrospective review of our experience with resected AIP and a review of the literature, we have identified five cardinal features of AIP in histology, imaging, serology, other organ involvement, and response to steroid therapy, which are summarized in the mnemonic HISORt. A combination of the HISORt criteria can be used to definitively diagnose a wide spectrum of manifestations of AIP.

The diagnostic criteria for autoimmune chronic pancreatitis: it is time to make a consensus

Autoimmune chronic pancreatitis (AIP) is increasingly being recognized as a worldwide entity. In 2002, the Japan Pancreas Society published diagnostic criteria for AIP. Since then, increased attention toward this relatively new disease entity has enabled more cases of AIP to be correctly diagnosed, allowing for proper management and avoidance of surgery. Retrospective inclusion of previously unrecognized or misdiagnosed cases of AIP has revealed an increasing number of cases that are not in full accordance with the Japanese diagnostic criteria. As a result, some groups have developed and cited their own criteria in the reporting of AIP, and the Japan Pancreas Society criteria have also undergone revision recently. The absence of consistent and uniform criteria has made the comparison of different cases diagnosed under various guidelines difficult. In this review, we discuss and compare the 4 current diagnostic criteria, focusing on their own strength and weakness with the aim of providing a framework for the development of unified criteria that represent an international consensus.

A Case Report of Autoimmune Pancreatitis Accompanied With Rapidly Developing Hyperglycemia and Hypertension in a Chronic Hemodialysis Patient

An 81-year-old man, with chronic renal failure due to chronic glomerulonephritis on maintenance hemodialysis (HD) for 4.5 years, was admitted to our hospital because of rapidly developing hyperglycemia and hypertension. He had been under good control on HD with no history of hyperglycemia. One month prior to admission he felt thirsty and generally fatigued, but did not inform medical staff of his symptoms. We diagnosed him as suffering from autoimmune pancreatitis (AIMP) associated with secondary diabetes mellitus, according to the typical feature of AIMP on endoscopic retrograde cholangiopancreatography and an elevated level of serum immunoglobulin G4 (IgG4). He was treated with insulin and a corticosteroid, following which, the diffuse narrowing of the main pancreatic duct improved and his serum IgG4 level reduced. AIMP is a rare but important complication in HD patients that requires prompt diagnosis and treatment; we are therefore reporting on a unique complication in a chronic HD patient.

Renal involvement in patients with autoimmune pancreatitis: CT and MR imaging findings

PURPOSE

To retrospectively evaluate computed tomographic (CT) and magnetic resonance (MR) imaging renal findings at clinical presentation, during treatment, and at follow-up in patients with autoimmune pancreatitis (AIP).

MATERIALS AND METHODS

This HIPAA-compliant study received institutional review board approval. All patients included had previously consented to the use of their medical records for the purpose of research. Forty-five patients (38 male and seven female patients; mean age, 64 years) with diagnosis of AIP were included. Forty patients underwent CT or MR imaging at clinical presentation; 33 patients (including five without imaging at presentation) underwent follow-up. CT and MR images were reviewed in consensus by two radiologists for the presence of renal involvement. Various features were evaluated. Clinical characteristics at presentation were compared between patients with and patients without renal involvement.

RESULTS

Of the 40 patients who underwent imaging at presentation, 14 (35%) had renal involvement (12 with parenchymal involvement and five with extraparenchymal involvement). Renal parenchymal lesions showed decreased enhancement and appeared as small peripheral cortical nodules, round or wedge-shaped lesions, or diffuse patchy involvement. Thirteen patients with renal involvement at presentation underwent a follow-up study. Renal lesions in 10 patients regressed (in nine, after steroid treatment) but progressed in three patients without steroid treatment. Renal lesions were found in two other patients during follow-up. No significant difference in the clinical characteristics was found between patients with and patients without renal involvement.

CONCLUSION

Renal involvement in patients with AIP is relatively common and predominantly involves the cortex of the kidney. The lesions improve after steroid treatment but can progress without steroid treatment.

Autoimmune pancreatitis with extreme elevation of DUPAN-2

An 80-year-old woman was admitted to our hospital with complaints of jaundice and liver dysfunction. She was found to have a high titer of serum IgG4, positive rheumatoid factor and marked elevation of DUPAN-2 (11,148 U/ml). Computed tomography showed swelling of the pancreas, and endoscopic retrograde cholangiopancreatography revealed diffuse irregular narrowing of the main pancreatic duct, which are typical findings of autoimmune pancreatitis. There was no evidence of malignancy. Administration of 30 mg/day of prednisolone was started. Computed tomography showed significant regression in the size of the pancreas, and the stenosis of the main pancreatic duct was improved on ERCP. The serum level of DUPAN-2 was also markedly decreased after the treatment.

Sclerosing cholangitis: a focus on secondary causes

Secondary sclerosing cholangitis (SSC) is a disease that is morphologically similar to primary sclerosing cholangitis (PSC) but that originates from a known pathological process. Its clinical and cholangiographic features may mimic PSC, yet its natural history may be more favorable if recognition is prompt and appropriate therapy is introduced. Thus, the diagnosis of PSC requires the exclusion of secondary causes of sclerosing cholangitis and recognition of associated conditions that may potentially imitate its classic cholangiographic features. Well-described causes of SSC include intraductal stone disease, surgical or blunt abdominal trauma, intra-arterial chemotherapy, and recurrent pancreatitis. However, a wide variety of other associations have been reported recently, including autoimmune pancreatitis, portal biliopathy, eosinophillic and/or mast cell cholangitis, hepatic inflammatory pseudotumor, recurrent pyogenic cholangitis, primary immune deficiency, and AIDS-related cholangiopathy. This article offers a comprehensive review of SSC.

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Pancreatic imaging: current and emerging technologies

This review discusses the current imaging modalities for the diagnosis and staging of solid and cystic pancreatic lesions and for the assessment of acute and chronic pancreatitis, and the future role of emerging technologies in the management of pancreatic diseases. Multidetector row spiral computed tomography is superior to conventional single-detector row spiral computed tomography in the detection and staging of pancreatic adenocarcinoma. Positron emission tomography is a sensitive but relatively nonspecific diagnostic modality. Positron emission tomography-computed tomography fusion may improve the staging accuracy for pancreatic cancer. Echo-enhanced ultrasound may have an emerging role in evaluating pancreatic masses. Endoscopic ultrasound with fine needle aspiration for cytology is the single best method for diagnosis and staging of nonmetastatic pancreatic cancer with a high accuracy for determining tumor resectability. In acute pancreatitis, a modification of the standard computed tomography severity index, which places greater emphasis on extrapancreatic complications, has shown superior correlation with various patient outcome measures. Endoscopic retrograde cholangiopancreatography is still the test of choice for morphological evaluation of chronic pancreatitis, whereas magnetic resonance cholangiopancreatography offers a noninvasive alternative in selected patients. Endoscopic ultrasound can be useful for detecting early chronic pancreatitis. Secretin-stimulated imaging techniques may eventually provide a noninvasive method of reliably assessing pancreatic exocrine function.

[Autoimmune pancreatitis--a surgical disease?]

The term autoimmune pancreatitis (AIP) describes a nonalcoholic, chronic lymphoplasmocytic pancreatitis. The lymphoplasmocytic infiltration is characterized by periductal localization of predominantly CD4-positive T cells, fibrosis, and acinar atrophy, frequently resulting in stenosis of the main pancreatic and distal common bile ducts. Imaging studies often reveal a diffuse narrowing of the pancreatic main duct and swelling of the pancreatic head wrongly suggesting the presence of a malignant tumor. Clinical signs include mild abdominal pain, jaundice, recurrent episodes of acute pancreatitis, and even new-onset diabetes mellitus. Additionally, AIP can be associated with other autoimmune diseases such as Sjögren's syndrome, primary sclerosing cholangitis, chronic inflammatory bowel diseases, and retroperitoneal fibrosis. Serological markers include autoantibodies and increased levels of gamma globulin and especially IgG4. Steroids seem to be effective in improving clinical symptoms as well as in the resolution of pancreatic and bile duct narrowing. This distinguishes AIP from other forms of pancreatitis and from pancreatic neoplasms. Further studies of the underlying pathophysiologic mechanisms, prognosis, and new diagnostic tools are needed to provide adequate and effective treatment in the future. In this article, we summarize the current knowledge about AIP and present 17 cases that underwent surgical resection at our institution from 2003 to 2004.

The Japanese diagnostic criteria for autoimmune chronic pancreatitis: is it completely satisfactory?

OBJECTIVES

Autoimmune chronic pancreatitis (AIP) is a very attractive disease to clinicians in terms of its dramatic response to the oral steroid therapy in contrast to ordinary chronic pancreatitis. In the year 2002, the Japan Pancreas Society published the diagnostic criteria of AIP, and many clinicians around the world use these criteria for its diagnosis. The purpose of this study was to evaluate whether the Japanese criteria for the diagnosis of AIP are adequate or not.

METHODS

We retrospectively analyzed the clinical, radiologic, laboratory, and histologic features of 31 patients with AIP who have been successfully treated with oral corticosteroid. All the enrolled patients showed normalization or marked improvement in symptoms, laboratory, and imaging findings after steroid treatment.

RESULTS

The mean patients' age was 56 years (range, 32-78 years) and comprised 25 males and 6 females. Seven patients who responded to the steroid did not satisfy the Japanese imaging criterion because the extent of irregular narrowing was less than one third of the entire length of main pancreatic duct. Among these 7 patients, 1 patient did not meet the laboratory and histopathologic criteria as well. Another 2 patients fulfilled the Japanese imaging criterion only and showed normal IgG level, negative results of autoantibody measurements, and nondiagnostic pancreatic histopathology. Taken together, 9 (29%) of the 31 patients did not meet the Japanese diagnostic criteria for AIP, yet responded to the steroid.

CONCLUSIONS

Clinicians may miss a substantial portion of AIP patients who may benefit from steroid therapy when the diagnosis is confined to those who satisfy the criteria proposed by the Japan Pancreas Society. It is necessary to convene a worldwide consensus to develop an improved diagnostic criteria for AIP.

Autoimmune pancreatitis: proposal of IgG4-related sclerosing disease

Autoimmune pancreatitis (AIP) is a peculiar type of pancreatitis of presumed autoimmune etiology. Many new clinical aspects of AIP have been clarified during the past 10 years, and AIP has become a distinct entity recognized worldwide. However, its precise pathogenesis or pathophysiology remains unclear. As AIP dramatically responds to steroid therapy, accurate diagnosis of AIP is necessary to avoid unnecessary surgery. Characteristic dense lymphoplasmacytic infiltration and fibrosis in the pancreas may prove to be the gold standard for diagnosis of AIP. However, since it is difficult to obtain sufficient pancreatic tissue, AIP should be diagnosed currently based on the characteristic radiological findings (irregular narrowing of the main pancreatic duct and enlargement of the pancreas) in combination with serological findings (elevation of serum gamma-globulin, IgG, or IgG4, along with the presence of autoantibodies), clinical findings (elderly male preponderance, fluctuating obstructive jaundice without pain, occasional extrapancreatic lesions, and favorable response to steroid therapy), and histopathological findings (dense infiltration of IgG4-positive plasma cells and T lymphocytes with fibrosis and obliterative phlebitis in various organs). It is apparent that elevation of serum IgG4 levels and infiltration of abundant IgG4-positive plasma cells into various organs are rather specific to AIP patients. We propose a new clinicopathological entity, "IgG4-related sclerosing disease", and suggest that AIP is a pancreatic lesion reflecting this systemic disease.

Identification of a novel autoantibody against pancreatic secretory trypsin inhibitor in patients with autoimmune pancreatitis

OBJECTIVES

Although autoimmune pancreatitis (AIP) has been recently recognized as a new disease entity of chronic pancreatitis, the clinical diagnosis of the disease remains disputed. Autoantibodies against carbonic anhydrase II and lactoferrin are detected in most patients with AIP, but not in about 10%. We undertook this study to determine whether additional autoantibodies are present in the serum level of AIP patients.

METHODS

We recruited 26 patients with AIP for the study. For comparison, we also recruited 53 patients with various pancreatic diseases and 12 healthy subjects. We immunoscreened human pancreatic cDNA library using patients' sera. Positive clones were analyzed by DNA sequencing and were constructed into a pGEX-4T-1 expression vector. The recombinant proteins were used as antigens in enzyme-linked immunosorbent assay to screen the subjects' sera for autoantibodies.

RESULTS

We cloned a cDNA encoding the pancreatic secretory trypsin inhibitor (PSTI). Among 26 patients with AIP, autoantibodies against PSTI were significantly positive in 11 (42.3%) by western blotting and in 8 (30.8%) by enzyme-linked immunosorbent assay, respectively. However, none of control subjects was positive for anti-PSTI antibodies.

CONCLUSIONS

These findings suggest that PSTI may be related to the pathogenesis of AIP, and autoantibodies against PSTI can be a useful diagnostic marker for the disease.

MRCP and MRI findings in 9 patients with autoimmune pancreatitis

AIM: To evaluate magnetic resonance cholangiopancre-atography (MRCP) findings in conjunction with magnetic resonance (MR) images in autoimmune pancreatitis (AIP) patients.

METHODS: Nine patients with AIP underwent MRI, MRCP, endoscopic retrograde cholangiopancreatography (ERCP), computed tomography, and ultrasonography. The MRCP and MR images taken before and after steroid therapy were reviewed and compared with other imaging modalities. The MRCP findings of the AIP cases were compared to those of 10 cases with carcinoma of the head of the pancreas.

RESULTS: On MRCP, the narrowed portion of the main pancreatic duct noted on ERCP was not visualized, while the non-involved segments of the main pancreatic duct were visualized. The degree of upstream dilatation of the proximal main pancreatic duct was milder than that seen in cases of pancreatic carcinoma. Stenosis or obstruction of the lower bile duct was detected in 8 patients. MR images showed enlargement of the pancreas with decreased signal intensity on T1-weighted MR images, increased signal intensity on T2-weighted MR images, and, in 3 patients, a hypointense capsule-like rim. After steroid therapy, the previously not visualized portion of the main pancreatic duct was seen, along with improvement of the bile duct stenosis. Pancreatic enlargement decreased, and the abnormal signal intensity on both T1- and T2-weighted MR images became isointense.

CONCLUSION: MRCP cannot differentiate irregular narrowing of the main pancreatic duct seen with AIP from stenosis of the main pancreatic duct seen with pancreatic carcinoma. However, MRCP findings in conjunction with MR imaging of pancreatic enlargement that shows abnormal signal intensity on T1- and T2-weighted MR images are useful in supporting a diagnosis of AIP.

Diagnostic criteria for autoimmune chronic pancreatitis revisited

Autoimmune chronic pancreatitis (AIP) is increasingly being recognized worldwidely, as knowledge of this entity builds up. Above all, AIP is a very attractive disease to clinicians in terms of its dramatic response to the oral steroid therapy in contrast to ordinary chronic pancreatitis. Although many characteristic findings of AIP have been described, definite diagnostic criteria have not been fully established. In the year 2002, the Japan Pancreas Society published the diagnostic criteria of AIP and many clinicians around the world use these criteria for the diagnosis of AIP. The diagnostic criteria proposed by the Japan Pancreas Society, however, are not completely satisfactory and some groups use their own criteria in reporting AIP. This review discusses several potential limitations of current diagnostic criteria for this increasingly recognized condition. The manuscript is organized to emphasize the need for convening a consensus to develop improved diagnostic criteria.

L’ictère nu : rôle du radiologue dans la prise en charge diagnostique et thérapeutique

The purpose of this article is to provide an update on imaging techniques for diagnosis and staging of clinical conditions leading to obstructive jaundice. Clinical and imaging findings of the most frequent diseases presenting as obstructive jaundice will be reviewed in order to optimize imaging strategies. Imaging and treatment strategies will be discussed in order to provide an optimal diagnosis and staging with the least invasive techniques in order to minimize complications in these patients.

Autoimmune pancreatitis: an underdiagnosed condition in Caucasians

Unlike in Japan, autoimmune pancreatitis is uncommon in the Western world, particularly in Europe. We report the first case of a Caucasian male with typical features of autoimmune pancreatitis in the UK. Recognizing autoimmune pancreatitis as a new clinical entity in Europe will change the management of many patients who have been labelled as having acute or chronic pancreatitis.

Autoimmune pancreatitis: radiologic findings in 20 patients

BACKGROUND

Autoimmune pancreatitis is a new clinical entity that is characterized by peculiar histopathologic and laboratory findings and by a dramatic clinical response to corticosteroid therapy. We evaluated the radiologic findings of autoimmune pancreatitis.

METHODS

Computed tomographic, magnetic resonance imaging, endoscopic retrograde cholangiopancreatographic, and ultrasonographic findings of 20 patients with autoimmune pancreatitis in our hospital between November 2000 and December 2003 were retrospectively reviewed regarding changes and ancillary findings in the pancreatic parenchyma, the main pancreatic duct, peripancreatic vessels, and distal common bile duct. In addition, follow-up images were reviewed for changes in any abnormality seen on the initial examinations.

RESULTS

Pancreatic parenchymal enlargement was invariably seen that was diffuse (n = 19) or focal (n = 1), with homogeneous contrast enhancement on computed tomography (n = 20) and magnetic resonance imaging (n = 15). Capsule-like rim enhancement was seen in six patients. There was focal (n = 18) or diffuse (n = 2) narrowing of the main pancreatic duct and it was usually multifocal (n = 17) in the former. Narrowing of the peripancreatic veins was seen in 14 patients. There was tapered (n = 15) or abrupt (n = 3) narrowing of the distal common bile duct in 18 patients, with contrast enhancement of the narrowed segment in eight. Invariably, changes in the pancreatic parenchyma, main pancreatic duct, peripancreatic vessels, and common bile duct were normalized on follow-up studies after steroid therapy.

CONCLUSION

In this series, common radiologic findings of autoimmune pancreatitis were (a) diffuse pancreas enlargement, (b) multifocal narrowing of the main pancreatic duct, (c) narrowing of peripancreatic veins, and (d) tapered narrowing of the distal common bile duct with frequent contrast enhancement. These findings were usually reversible with steroid therapy.

Autoimmune pancreatitis

Although the pathogenesis of autoimmune pancreatitis is unclear, recent evidence of clinical aspects are presented: (i) mild abdominal symptoms, usually without acute attacks of pancreatitis; (ii) occasional existence of obstructive jaundice; (iii) increased levels of serum gammaglobulin, IgG or IgG4; (iv) presence of autoantibodies; (v) diffuse enlargement of the pancreas; (vi) irregularly narrowing of the pancreatic duct (sclerosing pancreatitis) with often intra-pancreatic biliary stenosis or coexistence of biliary lesions (sclerosing cholangitis similar to primary sclerosing cholangitis: PSC) on endoscopic retrograde cholangiopancreatographic (ERCP) images; (vii) fibrotic changes with lymphocyte and IgG4-positive plasmacyte infiltration, and obliterative thrombo-phlebitis; (viii) occasional association with other systemic lesions such as sialoadenitis, retroperitoneal fibrosis, interstitial renal tubular disorders, and (ix) effective steroid therapy. In addition to pancreatic and extra-pancreatic lesions, diabetes mellitus is occasionally responsive to steroid therapy. Further studies are needed to clarify the pathogenesis.

Lymphoplasmacytic sclerosing pancreatitis

Lymphoplasmacytic sclerosing pancreatitis is a rare entity that has been described under many different names and constitutes a diagnostic challenge as it may simulate a neoplastic process. Herein, we report a case of a 61-year-old woman who presented to our institution complaining of left flank pain and was found to have normal levels of amylase and lipase. An abdominal magnetic resonance image showed thickening of the pancreatic tail and compression of the pancreatic duct. The radiographic differential included both chronic pancreatitis and a neoplastic process. She underwent an exploratory laparotomy, during which a pancreatectomy and splenectomy were performed. Grossly, the pancreas contained a yellowish white, firm homogeneous mass measuring 6.5 x 3.3 x 2.9 cm involving the entire pancreatic tail and hilum of the spleen. Histologically, pancreatic sections showed extensive fibrosis admixed with an inflammatory infiltrate. This infiltrate was composed mainly of lymphocytes with multiple germinal centers, as well as plasma cells and eosinophils that surrounded pancreatic ducts and extended into the peripancreatic adipose tissue. No malignancy was identified, and the process was diagnosed as lymphoplasmacytic sclerosing pancreatitis.

MR imaging of multifocal autoimmune pancreatitis in the pancreatic head and tail: a case report

Autoimmune pancreatitis, unlike alcoholic chronic pancreatitis, is a rare variant of pancreatitis. We describe the MR imaging findings in a 50-year-old man with multifocal autoimmune pancreatitis in the pancreatic head and tail. Our case demonstrates multifocal enlargement, diminished signal intensity on a T1-weighted image, and delayed enhancement with the capsule-like hypointense bands in a dynamic study. MR cholangiopancreatography is also found to be useful in evaluating the effectiveness of steroid therapy.

Autoimmune pancreatitis

The list of diseases associated with autoantibodies against tissues, cells, or specific autoantigens is growing, and many organs in the body are known to be affected by autoimmune injury. Until recently, the most well-known pancreatic autoimmune disorder was type 1 diabetes mellitus, where there is selective destruction of beta cells in the islets of Langerhans. Although an autoimmune process affecting the exocrine pancreas was suspected over four decades ago, it is only in the past 10 years or so that autoimmune chronic pancreatitis has been recognized as a distinct entity. Here we review the clinical, serologic, radiologic, and histologic features of autoimmune pancreatitis.

Atypical manifestations of pancreatitis with autoimmune phenomenon in an adolescent female

We report a case of an adolescent girl with atypical manifestations of pancreatitis with autoimmune phenomenon presenting with epigastralgia and back pain. While no abnormalities were detected on computed tomography and magnetic resonance imaging, apart from the absence of peripancreatic spread, laboratory and serological findings, such as hypergammaglobulinemia, a high titer of immunoglobulin G, a high titer of immunoglobulin G4, slight positivity for antinuclear antibodies, and positivity for autoantibodies to lactoferrin, were suggestive of autoimmune pancreatitis (AIP). Magnetic resonance cholangiopancreatography imaging (MRCP) visualized only the main pancreatic duct (MPD) in the pancreas head region. Proteoclastic enzyme inhibitor treatment was ineffective but the patient responded well to oral prednisolone. The patient and her family did not consent to endoscopic retrograde pancreatography or biopsy/histopathological examination. The case could not be diagnosed as AIP due to lack of typical diagnostic criteria, and thus the final diagnosis was considered pancreatitis with autoimmune phenomenon. We considered that the MRCP finding of partly visible MPD was due to diffuse irregular narrowing of the MPD. This case suggests that while MRCP imaging of the MPD may be helpful in the diagnosis of pancreatitis with autoimmune phenomenon, a negative result does not preclude such diagnosis.

Pancréatites chroniques et inflammatoires : apport des techniques d’imagerie en coupe

The role of diagnostic imaging in chronic and inflammatory pancreatitis is to detect structural changes of the ducts and pancreatic parenchyma, to assess the functional integrity of the gland, to detect associated complications, and to assist in management. These goals may be achieved using helical CT and MR imaging with secretin stimulation. In this review, the advantages of each technique are discussed and illustrated.

Autoimmune pancreatitis

Autoimmune pancreatitis is a type of idiopathic pancreatitis. It is also referred to as sclerosing pancreatitis, lymphoplasmatocytic sclerosing pancreatitis, chronic pancreatitis with irregular stenosis of the main pancreatic duct and as sclerosing pancreatocholangitis. Clinical characteristics of autoimmune pancreatitis are jaundice, abdominal pain, weight loss and diabetes mellitus. Radiologically, there is diffuse enlargement of pancreas with stenosis of pancreatic duct without calcifications in the pancreatic parenchyma. In autoimmune pancreatitis, antibodies against lactoferrin and carbonic anhydrase have been detected, but they are not specific because they are present in some other autoimmune diseases too. Also in autoimmune pancreatitis, there are increased levels of gammaglobulins and characteristically high titres of IgG4, which are a subtype of IgG. Autoimmune pancreatitis is usually treated successfully by prednisolone.

EUS findings in patients with autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis is an increasingly recognized benign condition with a presentation similar to pancreatic neoplasia but responds to corticosteroid therapy. Clinical features, ERCP, and CT findings have been described. This study assessed the EUS and EUS-guided FNA features of proven autoimmune pancreatitis.

METHODS

The diagnosis of autoimmune pancreatitis was based on examination of surgical resection specimens or typical clinical findings (elevated immunoglobulin G level, no evidence of malignancy, characteristic non-EUS imaging studies, and clinical improvement, especially in response to treatment with a corticosteroid).

RESULTS

Presenting manifestations in 14 patients included obstructive jaundice, abdominal pain, and weight loss. Ten patients underwent surgery (including exploratory surgery). Six were successfully treated with corticosteroid. EUS revealed diffuse hypoechoic pancreatic enlargement (8/14) or a focal irregular hypoechoic mass (6/14). Features of chronic pancreatitis were not noted. EUS-guided FNA of the pancreas was suggestive of chronic inflammatory pancreatitis in 9 of 12 patients. Celiac and peripancreatic lymphadenopathy (up to 3 cm in diameter) was present in 6 patients. EUS-guided FNA of lymph nodes (3/4) did not reveal evidence of malignancy. Vascular involvement was noted in 3 patients.

CONCLUSIONS

The EUS features of autoimmune pancreatitis are easily mistaken for malignancy. However, a diffusely hypoechoic, enlarged pancreas, together with chronic inflammatory cells in aspirated cytologic specimens, is supportive of the diagnosis of autoimmune pancreatitis. When combined with clinical data, EUS and EUS-guided FNA may support a diagnosis of autoimmune pancreatitis, may warrant a trial of corticosteroid, and thereby may prevent unnecessary surgery.

Lymphoplasmacytic sclerosing pancreatitis with obstructive jaundice: CT and pathology features

OBJECTIVE

The clinical presentation of lymphoplasmacytic sclerosing pancreatitis (LPSP) can be very similar to that of pancreatic cancer, with no statistically significant differences in the rates of abdominal pain, weight loss, jaundice, or levels of carcinoembryonic agent or cancer antigen 19-9. The purpose of this study is to describe and illustrate the CT features of LPSP presenting with obstructive jaundice and to correlate CT and pathology findings.

MATERIALS AND METHODS

Five patients with LPSP were evaluated. Morphologic features of the pancreas on CT scans, including the size of the pancreas, presence or absence of a mass, segmental difference of contrast enhancement, pancreatic duct, major pancreatic vasculature, and biliary tract, were retrospectively evaluated and correlated with histopathology. The degree of contrast enhancement of the pancreas was compared in 10 patients without LPSP, who were scanned with the same protocol.

RESULTS

CT scans showed diffuse (n = 2) or focal (n = 3) enlargement of the pancreatic head. The normal lobular appearance of the pancreas was effaced, and the gland appeared featureless in the involved region. Enlarged areas showed an enhancement pattern similar to that of the rest of the pancreas, and no segmental difference of contrast enhancement was identified. Pancreatic duct dilatation was not seen in any patient. Thickening and contrast enhancement of the common bile duct wall (n = 4) and gallbladder wall (n = 3) were observed and were pathologically correlated with inflammatory infiltrate and fibrosis of the common bile duct (n = 3) and gallbladder (n = 1).

CONCLUSION

When these findings are encountered, further evaluation with serologic tests or biopsy may aid in the diagnosis of LPSP.

Overlap syndrome of autoimmune pancreatitis and cholangitis associated with secondary Sjögren's syndrome

In approximately 25% of patients with acute or chronic pancreatitis the cause remains unclear. Despite progress in understanding so-called idiopathic pancreatitis, more diagnostic criteria are needed. We report on a patient who presented with jaundice, but without pain or fever. Under the assumption of pancreatic cancer the patient underwent hemipancreatoduodenectomy. Histological examination showed chronic sclerosing inflammation of the pancreas and bile ducts without any signs of malignancy. Ten weeks later he developed bilateral parotid swelling and recurrent bouts of fever. Again liver enzymes were elevated and unsuccessfully treated with antibiotics for bacterial cholangitis. Further biopsies from submandibular gland, lymph nodes and liver again showed chronic sclerosing inflammation with lymphoplasmacytic infiltration. For sicca symptoms the diagnosis of a primary Sjogren's syndrome was proposed. However, with corticosteroid treatment the patient improved remarkably but after tapering he relapsed. On the basis of established criteria, we diagnosed autoimmune pancreatitis with (1) diffuse swelling of the pancreas, (2) irregularities of the pancreatic duct, (3) lymphoplasmacytic infiltration, (4) response to corticosteroids, (5) hypergammaglobulinaemia, and (6) disproportionately raised IgG4. In addition, the patient fulfilled the criteria for secondary Sjogren's syndrome. Autoimmune pancreatitis may present as an isolated or syndromic disease. It is an autoimmune disorder of unknown cause and should be included in the differential diagnosis of pancreatic disorders.

Lymphoplasmacytic sclerosing (autoimmune) pancreatitis

Lymphoplasmacytic sclerosing pancreatitis (LPSP), also known as autoimmune pancreatitis or nonalcoholic, duct destructive chronic pancreatitis, has been increasingly recognized in the past decade as a histologically distinctive type of pancreatitis that affects middle-aged patients who lack the typical risk factors for chronic pancreatitis (alcohol abuse in particular). LPSP is sometimes associated with other autoimmune diseases or fibroinflammatory lesions, although in some patients, pancreatic and biliary involvement represent the only known disease process. Many patients present with pancreatic masses clinically and radiographically simulating pancreatic carcinoma, and associated bile duct strictures enhance the resemblance. Elevated serum IgG4 levels have been described in patients with LPSP and have been used to distinguish LPSP from pancreatic carcinoma preoperatively. Although there is some heterogeneity of pathologic findings, resected cases of LPSP typically demonstrate dense periductal lymphoplasmacytic inflammation, periductal and parenchymal fibrosis, and obliterative venulitis; neutrophilic infiltration of the ductal epithelium ("granulocytic epithelial lesions") may also occur. Large tumor-like masses of fibroinflammatory tissue ("reactive fibroinflammatory pseudotumors") may develop and extend beyond the pancreas. Following surgical resection, a few patients suffer recurrence of fibroinflammatory lesions in the pancreatobiliary tree, or they may develop other manifestations of autoimmune disease elsewhere in the body. However, the overall prognosis is excellent. Response to steroid therapy has been noted. Current studies are focusing on identifying additional preoperative diagnostic tests and on characterizing possible variants of LPSP. This review presents the defining clinical and pathologic features of LPSP and discusses the ongoing efforts to understand the pathogenesis of this disease.

Autoimmune pancreatitis: increasing evidence for a clinical entity with various patterns

Autoimmune pancreatitis is a clinical entity with many different clinical and biological characteristics that make diagnosis difficult. Sensitive and specific pancreatic antibodies are still lacking to assess the diagnosis as is the availability of interpretable pathological specimens. However, suggestive features consist mainly of radiological findings and clinical anomalies, particularly if there are associated autoimmune-related diseases. The immunological pathway is probably of cell-mediated origin, although various autoantibodies, insensitive and non-specific, may exist. Finally, many studies are needed to define more efficient diagnostic criteria and to discover the true prevalence of autoimmune pancreatitis.

Autoimmune pancreatitis: imaging features

PURPOSE

To retrospectively determine imaging findings in patients with autoimmune pancreatitis.

MATERIALS AND METHODS

Twenty-nine patients (25 male and four female; mean age, 56 years; range, 15-82 years) with histopathologic diagnosis of autoimmune pancreatitis were examined. Data were reviewed by two radiologists in consensus. Imaging findings for review included those from helical computed tomography (CT), 25 patients; magnetic resonance (MR) imaging with MR cholangiopancreatography (MRCP), four patients; endoscopic ultrasonography (US), 21 patients; endoscopic retrograde cholangiopancreatography (ERCP), 19 patients; and percutaneous transhepatic cholangiography, one patient. Images were analyzed for appearances of pancreas, biliary and pancreatic ducts, and other findings, such as peripancreatic inflammation, encasement of vessels, mass effect, pancreatic calcification, peripancreatic nodes, and peripancreatic fluid collection. Follow-up images were available in nine patients. Serologic markers such as serum immunoglobulin G (IgG) and antinuclear antibody levels were available in 12 patients.

RESULTS

CT showed diffuse (n = 14) and focal (n = 7) enlargement of pancreas. Seven patients had minimal peripancreatic stranding, with lack of vascular encasement, calcification, or peripancreatic fluid collection. Nine patients had enlarged peripancreatic lymph nodes. MR imaging showed focal (n = 2) and diffuse (n = 2) enlargement with rimlike enhancement in one. MRCP revealed pancreatic duct strictures in two and sclerosing cholangitis-like appearance in one. Endoscopic US showed diffuse enlargement of pancreas with altered echotexture in 13 patients and focal mass in the head in six. ERCP showed stricture of distal common bile duct in 12 patients, irregular narrowing of intrahepatic ducts in six, diffuse irregular narrowing of pancreatic duct in nine, and focal stricture of proximal pancreatic duct in six. Serologic markers showed increased IgG and antinuclear antibody levels in seven of 12 patients. At follow-up, CT abnormalities and common bile duct strictures resolved after steroid therapy in three patients.

CONCLUSION

Features that suggest autoimmune pancreatitis include focal or diffuse pancreatic enlargement, with minimal peripancreatic inflammation and absence of vascular encasement or calcification at CT and endoscopic US, and diffuse irregular narrowing of main pancreatic duct, with associated multiple biliary strictures at ERCP.

Autoimmune chronic pancreatitis

In recent years a peculiar type of chronic pancreatitis with underlying autoimmunity has been described. Lymphoplasmacytic infiltration and fibrosis on histology and elevated IgG levels or detected autoantibodies on laboratory data support the concept of autoimmune chronic pancreatitis (AIP). Pancreatic imaging reveals a rare association of diffuse enlargement of the pancreas and irregular narrowing of the main pancreatic duct, which is unique and specific to AIP. Although AIP is not a common disease, it is increasingly being recognized as knowledge of this entity builds up. Clinically it is very important to be aware of this disease because AIP can clinically disguise as pancreaticobiliary malignancies, ordinary chronic, or acute pancreatitis. Above all, AIP is a very attractive disease to clinicians in terms of its dramatic response to oral steroid therapy in contrast to ordinary chronic pancreatitis. This review discusses the clinical, laboratory, histologic, and imaging findings that are seen in patients with AIP, especially focusing on the diagnosis.

T cell lymphoplasmacellular and eosinophilic infiltration of the pancreas with involvement of the gallbladder and duodenum in non-alcoholic duct-destructive chronic pancreatitis

BACKGROUND

Non-alcoholic duct destructive chronic pancreatitis is a rare entity with specific pathological features. The majority of the patients are from Japan. We report a case with involvement of the distal bile duct, the gallbladder, the duodenum and the ampulla, and present a review of patients from Europe and the USA since 1997.

CASE PRESENTATION

A 56-year-old man presented with a 3-month history of mild acute pancreatitis and obstructive jaundice, followed by increasing weight loss, lethargy and epigastric pain. CT showed a mass in the head of the pancreas. ERCP demonstrated a smooth stricture of the intra-pancreatic main bile duct and an irregular, incomplete, stricture in the main pancreatic duct. A pancreatic cancer could not be reliably excluded, and, therefore, he underwent a pylorus-preserving Kausch-Whipple's pancreatoduodenectomy.

RESULTS

Histopathology showed typical peri-ductal T cell-rich lymphoplasmacellular and eosinophilic infiltration of the pancreas, with involvement of the distal bile duct but, also, unusual inflammatory infiltration of the gallbladder, the duodenum and the ampulla.

CONCLUSION

The inflammatory process in non-alcoholic duct-destructive chronic pancreatitis can affect the entire pancreato-biliary region and mimics pancreatic cancer. Currently, there are no definitive criteria for pre-operative diagnosis, so it is very difficult for one to avoid resection.

Contrast-enhanced sonography of autoimmune pancreatitis: comparison with pathologic findings

OBJECTIVE

We evaluated the vascularity of autoimmune pancreatitis lesions on contrast-enhanced harmonic gray scale sonographic images in comparison with the pathologic findings.

METHODS

Six patients with autoimmune pancreatitis were examined. All patients held their breath from 20 to 50 seconds after the injection of a contrast agent while the vascularity of the lesion was examined by contrast-enhanced harmonic gray scale sonography (early phase), and lesion enhancement was monitored at about 90 seconds after the injection while the patients held their breath for a few seconds (delayed phase). We then compared the vascularity on the contrast-enhanced harmonic gray scale sonographic images with the pathologic findings (fibrosis and inflammation) in all lesions. The vascularity of 3 of the 6 lesions was also evaluated by contrast-enhanced harmonic gray scale sonography before and after treatment with corticosteroids.

RESULTS

The autoimmune pancreatitis lesions exhibited mild (n = 1), moderate (n = 3), or marked (n = 2) enhancement throughout almost the entire lesions in both the early and delayed phases. The grade of lesion vascularity on the contrast-enhanced harmonic gray scale sonographic images correlated with the pathologic grade of inflammation and inversely correlated with the grade of fibrosis associated with autoimmune pancreatitis. The vascularity of all 3 lesions had decreased on the contrast-enhanced harmonic gray scale sonographic images after steroid therapy.

CONCLUSIONS

Contrast-enhanced harmonic gray scale sonography may be useful for evaluating the vascularity of autoimmune pancreatitis lesions and the therapeutic efficacy of steroid therapy.

Clinical and imaging features of autoimmune pancreatitis with focal pancreatic swelling or mass formation: comparison with so-called tumor-forming pancreatitis and pancreatic carcinoma

OBJECTIVES

Autoimmune pancreatitis (AIP) with a mass formation or swollen pancreas located in one or two segments of the gland (focal type AIP) has been reported. The aims of this study were to elucidate the relationship of the disease entity between this focal variant and so-called tumor-forming pancreatitis (TFP) and to describe the clinical and imaging features discriminating focal AIP from pancreatic carcinoma (Pca).

METHODS

The clinical, radiologic, and pathologic profiles of nine patients with focal AIP were reviewed retrospectively and compared with those of 11 patients with alcohol-induced TFP and 80 patients with Pca.

RESULTS

The patients with focal AIP were predominantly older (mean age 64.7 +/- 13.6 yr, range 28-78 yr), male, and presenting with obstructive jaundice or focal pancreatic enlargement accompanied by mild abdominal symptoms. In comparison, the patients with alcohol-induced TFP who were mostly middle-aged (mean age 50.1 +/- 7.95 yr, range 39-62 yr), male, and often had attacks of pancreatitis associated with findings of CT scans showing pseudocysts or peripancreatic effusion. Focal AIP usually demonstrated no abnormalities on pancreatograms downstream from the stricture or obstruction and often presented few contrast-filled side branches in the area of main pancreatic duct (MPD) stenosis. These characteristics were similar to the imaging features of Pca. Significant factors differentiating focal AIP from Pca were lower serum levels of CA19-9, homogeneous delayed enhancement evident in dynamic CT scans, and ERCP findings exhibiting a longer stenosed MPD and a thinner MPD upstream from the stricture.

CONCLUSIONS

Focal AIP is associated with clinical and radiologic features that are different from those of alcohol-induced TFP. In TFP there are two causative factors, namely, AIP and alcohol-induced chronic pancreatitis. Differential diagnosis of focal AIP from Pca seems to be possible in many cases by evaluating imaging findings such as dynamic CT and ERCP, although focal AIP sometimes shows clinical and radiologic features similar to those of Pca.

Involvement of the biliary system in autoimmune pancreatitis: a follow-up study

BACKGROUND & AIMS

The aim of this study was to define the bile duct changes associated with autoimmune pancreatitis.

METHODS

Eight patients with autoimmune pancreatitis were followed for a mean of 4 years. The clinical features of these patients, including extrapancreatic bile duct changes, were examined by using biochemical parameters and several imaging modalities. Pathologic features of the pancreas and liver were examined by using the biopsy specimens of 7 patients.

RESULTS

Diffuse or focal narrowing of the main pancreatic duct was observed in all patients. Histologic examination of the pancreas showed lymphoplasmacyte infiltration with severe fibrosis and acinar cell depletion. In 6 patients extrapancreatic bile duct changes such as stricture of the bile duct at hilus or intrahepatic area were observed. In 2 patients abnormalities in the bile duct and pancreas were detected simultaneously at diagnosis, and changes in the bile duct were observed later in 4 patients. Lymphoplasmacyte infiltration and fibrosis were observed in the portal area of all 7 liver biopsy samples. Five of the patients with bile duct changes received steroid therapy, and the pathological changes improved.

CONCLUSIONS

Extrapancreatic bile duct changes are frequently associated with autoimmune pancreatitis. Similar pathogenic mechanism might produce the biliary tract and pancreatic abnormalities in autoimmune pancreatitis resulting in a similar histopathology in the liver and pancreas and response to steroid therapy.

Approach to idiopathic recurrent pancreatitis

Acute pancreatitis is caused by acute or chronic alcohol intake or choledocholithiasis in approximately 80% of cases. In the absence of alcohol abuse or gallstones, a variety of established and putative factors must be considered, any of which can cause a single or recurrent attacks of acute pancreatitis. When the underlying cause eludes detection following an initial thorough search and leads to a second attack, the term idiopathic acute recurrent pancreatitis (IARP) is applied. This article discusses IARP and its work-up.

Evaluation of contrast enhancement patterns in pancreatic tumors by coded harmonic sonographic imaging with a microbubble contrast agent

OBJECTIVE

The purpose of the study was to assess patterns of primary pancreatic lesions by contrast-enhanced sonography for differentiating ductal carcinomas from other pancreatic tumors.

METHODS

One hundred six consecutive patients with pancreatic masses, consisting of 83 ductal carcinomas, 7 endocrine carcinomas, 5 intraductal papillary mucinous tumors, 3 cases of autoimmune-related pancreatitis, 3 solid pseudopapillary tumors, 2 cases of chronic pancreatitis, 1 serous cystadenoma, 1 osteoclastoid giant cell tumor, and 1 follicular lymphoma, were examined by contrast-enhanced sonography with coded harmonic imaging in a phase inversion harmonic technique. The contrast enhancement patterns were assessed, and specimens removed during pancreatectomy were subjected to pathologic examination.

RESULTS

Internal tumoral vascularity was detected in 47 (56.6%) of the 83 ductal carcinomas. Vascular image spreading and homogeneous staining throughout the tumors were observed in all endocrine carcinomas. Two of the 5 intraductal papillary mucinous tumors were positive for enhancement effects. Enhancement effects were observed in all 3 cases of autoimmune-related pancreatitis, but the degree varied. There was a significant correlation between the intensity of enhancement effects and the ratio of patent vessels in the tumors (P < .05).

CONCLUSIONS

Vascularity was detected by contrast-enhanced sonography in only about half of the ductal carcinomas, confirming the difficulty in distinguishing those tumors from other pancreatic tumors. There was a correlation between the patency of the vessels in the tumors and their vascularity.

A case of autoimmune pancreatitis responding to steroid therapy. Evidence of histologic recovery

We report a case of autoimmune pancreatitis without obvious evidence of autoimmunological participation, which responded well to steroid treatment and provided histologic and radiographic evidence for this improvement. A 68-year-old woman presented abdominal fullness, diffuse pancreatic swelling on abdominal computed tomography and ultrasonography, and diffuse narrowing of the main pancreatic duct on endoscopic retrograde pancreatography. Transgastric aspiration needle biopsy of the body of the pancreas performed under endoscopic ultrasonography showed severe atrophy of acinar cells, infiltration of T lymphocytes. She was diagnosed as having autoimmune pancreatitis without obvious evidence of autoimmunological participation. Administration of 30 mg/day of predonisolone was started. Computed tomography showed marked improvement of the diffuse swelling of the pancreas, and endoscopic retrograde pancreatograpy showed amelioration of the narrowing of the main pancreatic duct after the start of treatment. Pancreatic tissue obtained by needle biopsy after the start of treatment with predonisolone revealed marked histologic improvement, including amelioration of the fibrosis, and infiltration of inflammatory lymphocytes, and a substantial increase in the number of pancreatic acinar cells. The present report is the first to demonstrate histologic recovery of autoimmune pancreatitis after steroid therapy.

Diagnosis of pancreatic cancer using fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET) --usefulness and limitations in "clinical reality"

The present review will provide an overview of the literature concerning the FDG PET diagnosis of pancreatic cancer and a summary from our experience of 231 cases of pancreatic lesions. FDG PET can effectively differentiate pancreatic cancer from benign lesion with high accuracy. Newly-developed PET scanners can detect small pancreatic cancers, up to 7 mm in diameter, by their high resolution, which could make a great contribution to the early detection of resectable and potentially curable pancreatic cancers. FDG PET is useful and cost-beneficial in the pre-operative staging of pancreatic cancer because an unexpected distant metastasis can be detected by whole-body PET in about 40% of the cases, which results in avoidance of unnecessary surgical procedures. FDG PET is also useful in evaluation of the treatment effect, monitoring after the operation and detection of recurrent pancreatic cancers. However, there are some drawbacks in PET diagnosis. A relatively wide overlap has been reported between semiquantitative uptake values obtained in cancers and those in inflammatory lesions. As for false-positive cases, active and chronic pancreatitis and autoimmune pancreatitis sometimes show high FDG accumulation and mimic pancreatic cancer with a shape of focal uptake. There were 8 false negative cases in the detection of pancreatic cancer by FDG PET, up to 33 mm in diameter, mainly because of their poor cellularity in cancer tissues. In addition, there are 19% of cancer cases with a decline in FDG uptake from 1 hr to 2 hr scan. FDG PET was recently applied to and was shown to be feasible in the differential diagnosis of cystic pancreatic lesions, such as intraductal papillary mucinous tumor of the pancreas. Further investigations are required to clarify the clinical value of FDG PET in predicting prognosis of the pancreatic patients.

Autoimmune Pancreatitis Presenting as a Mass in the Head of the Pancreas: A Diagnosis to Differentiate from Cancer

We report a case of autoimmune pancreatitis presenting as a mass in the head of the pancreas that was successfully diagnosed without pancreaticoduodenectomy. The patient was a 64-year-old man who had no complaint. A routine physical checkup unexpectedly revealed mild diabetes and a low-echoic mass in the pancreatic head. The diagnosis was made by noting irregular narrowing of the main pancreatic duct, hypergammaglobulinemia, and increased immunoglobulin G levels. An open wedge biopsy of the mass was performed; this showed a marked fibrosis with lymphocyte- or macrophage-predominant inflammatory infiltrates. Immunohistochemical study revealed that the remnant acinar cells expressed Fas (CD95) ligand and not Fas. We review some of the literature and discuss various features and diagnostic clues of autoimmune pancreatitis. Awareness of this pathologic condition may prevent confusion with pancreatic malignancy and unnecessary surgery.