Undifferentiated (anaplastic) carcinoma of the pancreas showing sarcomatous change and neoplastic cyst formation

Poorly enhanced areas of pancreatic adenocarcinomas on late-phase dynamic computed tomography: comparison with pathological findings

OBJECTIVES

The aim of the study was to retrospectively compare image findings of poorly enhanced areas (PEAs) of pancreatic adenocarcinomas that show almost no enhancement or obviously hypoattenuating area relative to the surrounding carcinoma on late-phase dynamic computed tomography (CT) with pathological findings.

METHODS

Thirty-nine patients with pancreatic adenocarcinoma underwent dynamic CT and surgery. Poorly enhanced areas were classified according to their size, attenuation value, position, and border on CT imaging and signal intensity on magnetic resonance imaging.

RESULTS

Of the 33 PEAs, 12 showed neoplastic duct-like structure that contained both large tumor gland and dilated pancreatic duct with atypia, 11 showed necrosis, 4 showed retention cyst, 2 showed dilated pancreatic duct without atypia or with limited invasion, 1 showed mucin, and 3 showed no remarkable differences in characteristics compared with surrounding tissue. Neoplastic duct-like structures tended to be well defined (P < 0.01). Necrotic portions tended to show a high attenuation value (P < 0.01) and central position (P < 0.01) and were ill defined (P < 0.01). Retention cysts tended to show a peripheral position (P < 0.01).

CONCLUSIONS

Poorly enhanced areas corresponded to cystic, necrotic, and mucinous components. Image findings demonstrated these characteristics. Necrotic component can be visualized and distinguished with other components and can be a prognostic factor.

Molecular classification of neoplasms of the pancreas

The recent sequencing of the pancreatic cancer genome provides unprecedented insight into the fundamental nature of this deadly malignancy. Although much work still needs to be done, a molecular classification of neoplasms of the pancreas is emerging. Molecular genetics have been used to identify unique clinical subtypes of pancreatic cancer, to guide the clinical diagnosis of pancreatic tumors, and to identify targeted therapies for select pancreatic neoplasms. This review examines the emerging molecular classification of neoplasms of the pancreas. This classification does not ignore previous histology-based classification systems but instead embraces them, creating an integrated histological-molecular classification.

Pathomorphologic study of undifferentiated carcinoma in seven cases: relationship between tumor and pancreatic duct epithelium

BACKGROUND/PURPOSE

By the time undifferentiated carcinoma is detected, it has formed a large mass, and it is reportedly difficult to pathologically observe its relationship with the pancreatic duct. In this study, we examined the pancreatic ducts of seven patients of surgical samples, and pathomorphologically investigated the relationship between the adenocarcinomatous and sarcomatous components and the pattern of tumor extension. In addition, we evaluated the usefulness of pancreatic juice cytology by comparison with the findings of the main pancreatic duct (MPD).

METHODS

Seven primary undifferentiated carcinomas of the pancreas (from three male and four female patients with a mean age of 59 years) were analyzed. Histopathological evaluation was based on the WHO diagnostic criteria. Pancreatic juice cytology was performed and evaluated in two patients.

RESULTS

All the undifferentiated carcinomas contained adenocarcinomatous and sarcomatous components, and two had a distinct glandular structure. However, we could not pathomorphologically confirm the continuity of the adenomatous with the sarcomatous components in any of the patients. Three undifferentiated carcinomas contained osteoclast-like giant cells. Pathological observation of the tumor and MPD was possible in three of the seven undifferentiated carcinomas. PanIN-3 was observed in the MPD of three patients, suggesting extension into the MPD. In one of these three, the tumor presented intraductal growth in the MPD, and preoperative pancreatic juice cytology revealed atypical cells with osteoclast-like giant cells. In the remaining two, the tumor extraductally compressed the MPD upward.

CONCLUSIONS

Undifferentiated carcinoma showed two patterns of cancer extension: (1) invasion and expansive growth during the sarcomatous transformation of adenocarcinoma, and (2) intraductal extension. In addition, some undifferentiated carcinomas showed extension in the MPD. Of note, postoperative pancreatic juice cytology may be useful for the diagnosis.

Two critical genes (HLA-DRB1 and ABCF1)in the HLA region are associated with the susceptibility to autoimmune pancreatitis

We have previously reported that autoimmune pancreatitis (AIP) is a bioclinical entity characterized by high serum immunoglobulin G4 concentrations and association with the HLA-DRB1*0405-DQB1*0401 haplotype. However, the precise identity of gene(s) within this haplotype directly responsible for AIP pathogenesis is yet to be established. To dissect the genetic contribution of the incriminated haplotype, we have now performed an association analysis within the human leukocyte antigen (HLA) region using various types of polymorphic markers. Genomic DNAs from 43 AIP patients and 213 unrelated Japanese controls were used in this analysis. In each DNA sample, we established the genotype of 25 microsatellite markers distributed throughout the HLA region, that of single nucleotide polymorphism within the 5'-flanking regions of the TNFA and IkBLI (also known as NFKBIL1) as well as HLA class I and II genes. The HLA-linked susceptibility regions for AIP were localized to two segments: HLA-DRB1 (*0405; OR = 3.20, P = 0.00063, Pc = 0.0016) -DQB1 (*0401; OR = 3.29, P = 0.00046, Pc = 0.0069) in the HLA class II and C3-2-11 microsatellite (allele 219; OR = 2.96, P = 0.0076, Pc = 0.099) in the HLA class I regions. Upon stratification analysis in search for a synergistic effect given the extensive linkage disequilibrium within the major histocompatibility complex, it was established that each segment contributed to disease pathogenesis. The two critical HLA regions for susceptibility to AIP are limited to the HLA-DRB1*0405-DQB1*0401 in the class II and the ABCF1 proximal to C3-2-11, telomeric of HLA-E, in the class I regions.

Hyper-IgG4 disease: report and characterisation of a new disease

BACKGROUND

We highlight a chronic inflammatory disease we call 'hyper-IgG4 disease', which has many synonyms depending on the organ involved, the country of origin and the year of the report. It is characterized histologically by a lymphoplasmacytic inflammation with IgG4-positive cells and exuberant fibrosis, which leaves dense fibrosis on resolution. A typical example is idiopathic retroperitoneal fibrosis, but the initial report in 2001 was of sclerosing pancreatitis.

METHODS

We report an index case with fever and severe systemic disease. We have also reviewed the histology of 11 further patients with idiopathic retroperitoneal fibrosis for evidence of IgG4-expressing plasma cells, and examined a wide range of other inflammatory conditions and fibrotic diseases as organ-specific controls. We have reviewed the published literature for disease associations with idiopathic, systemic fibrosing conditions and the synonyms: pseudotumour, myofibroblastic tumour, plasma cell granuloma, systemic fibrosis, xanthofibrogranulomatosis, and multifocal fibrosclerosis.

RESULTS

Histology from all 12 patients showed, to varying degrees, fibrosis, intense inflammatory cell infiltration with lymphocytes, plasma cells, scattered neutrophils, and sometimes eosinophilic aggregates, with venulitis and obliterative arteritis. The majority of lymphocytes were T cells that expressed CD8 and CD4, with scattered B-cell-rich small lymphoid follicles. In all cases, there was a significant increase in IgG4-positive plasma cells compared with controls. In two cases, biopsies before and after steroid treatment were available, and only scattered plasma cells were seen after treatment, none of them expressing IgG4. Review of the literature shows that although pathology commonly appears confined to one organ, patients can have systemic symptoms and fever. In the active period, there is an acute phase response with a high serum concentration of IgG, and during this phase, there is a rapid clinical response to glucocorticoid steroid treatment.

CONCLUSION

We believe that hyper-IgG4 disease is an important condition to recognise, as the diagnosis can be readily verified and the outcome with treatment is very good.

Endoscopic ultrasound guided fine needle aspiration biopsy of autoimmune pancreatitis: diagnostic criteria and pitfalls

Autoimmune pancreatitis (AIP) is a benign inflammatory disease of the pancreas that mimics pancreatic malignancy both clinically and radiologically. The fine needle aspiration biopsy (FNAB) features of AIP have not previously been documented. We report our experience with AIP, highlight pitfalls, and perform a comprehensive analysis of the cytomorphologic features of this condition. We identified 16 patients with AIP, initially evaluated by endoscopic ultrasound (EUS)-guided FNAB, 11 of whom subsequently underwent a pancreatoduodenectomy. We compared these to a cohort of EUS-guided aspirates from ductal carcinoma of the pancreas (n = 16) and chronic pancreatitis, not otherwise specified (NOS) (n = 19). On all 51 cases, we semiquantitatively evaluated presence and atypia of ductal cells, presence and cellularity of stromal fragments, and inflammatory cells, type and distribution. Fifty percent (8 of 16) of the AIP cases presented as obstructive jaundice. EUS and CT scan showed mass lesions in 10 and 6 cases, respectively. There were three false-positive cytologic diagnoses, an adenocarcinoma, a solid-pseudopapillary tumor and a mucinous neoplasm. Ductal epithelium was inconspicuous and was seen in 6 cases. The FNAB samples showed background lymphocytes in three AIP cases, a feature absent in the control cohort. Stromal fragments with embedded lymphocytes (greater than 30 per 60x) were seen in 37.5% of AIP cases and only rarely with adenocarcinoma (12.5%) and pancreatitis, NOS (0%). The cellularity of stromal fragments was significantly higher in AIP than in the control group. The presence of stromal fragments of high cellularity with a lymphoid infiltrate in conjunction with clinical and radiology findings could potentially both establish a diagnosis of AIP and exclude carcinoma, thus preventing pancreatic resection.

Pancreatic ductal adenocarcinomas with cystic features: neither rare nor uniform

Cystic tumors of the pancreas are uncommon but important because of their diverse pathology and biology. Their wide spectrum also includes cystic variants of otherwise solid tumors, such as cystic endocrine tumors, cystic acinar cell carcinomas and ductal adenocarcinomas with cystic changes. In this study, we screened pancreatic ductal adenocarcinomas and their variants for macrocystic changes and determined the nature of the cysts (neoplastic vs non-neoplastic). Of 483 tumors 38 (8%) had cystic features. The largest group consisted of 24 pancreatic ductal adenocarcinomas showing a large-gland pattern with small cysts whose diameter varied between 0.5 and 1.8 cm. The epithelial lining of these cysts was generally positive for CEA (83%) and/or MUC1 (71%) and MUC5AC (74%). p53 was positive in 57% of the cases. The second group of cystic tumors (8/483) showed degenerative cystic cavities with diameters ranging between 1 and 6 cm. This group consisted of poorly differentiated pancreatic ductal adenocarcinomas, undifferentiated carcinomas with or without osteoclast-like giant cells and one adenosquamous carcinoma. In the third group of cystic tumors there were four pancreatic ductal adenocarcinomas containing tumor-related retention cysts. Their epithelial cells were positive for MUC5AC, but negative for CEA, MUC1 and p53. The fourth group consisted of two pancreatic ductal adenocarcinomas showing closely attached pseudocysts caused by tumor-associated pancreatitis. The results indicate that a considerable number of pancreatic ductal adenocarcinomas and their variants display cystic features and must therefore be considered in the differential diagnosis of cystic neoplasms of the pancreas. Moreover, not all of the cystic structures we observed were neoplastic in nature. They may also represent non-neoplastic changes, such as retention cysts and inflammatory pseudocysts.

Distinct clinicopathological entity 'autoimmune pancreatitis-associated sclerosing cholangitis'

Autoimmune pancreatitis (AIP) is a recently proposed disease entity, in which an elevated serum IgG4 is characteristic. This disease is sometimes associated with other inflammatory diseases: Sjögren's disease, or sclerosing cholangitis. The aim of the present paper was to examine the difference in pathophysiology between AIP-associated sclerosing cholangitis (AIP-SC) and primary sclerosing cholangitis (PSC). The clinicopathological findings and the immunohistochemical expressions of IgG subclasses (IgG1, IgG2, IgG3, and IgG4) were evaluated for the two aforementioned diseases (six patients with each disease). Radiologically, the extrahepatic bile duct was involved in AIP-SC, whereas both extrahepatic and intrahepatic bile ducts were involved in PSC. Clinically, bile duct lesions in the former responded well to steroid therapy. Histologically, various degrees of mononuclear cell infiltration and fibrosis around bile ducts and portal tracts were found in all patients. Immunohistochemically, the IgG4-positive plasma cell/mononuclear cell ratio was significantly higher in AIP-SC than in PSC (P < 0.05). The IgG4-positive plasma cell/mononuclear cell ratio is a useful index to help distinguish AIP-SC from PSC. A mechanism similar to that involved in AIP may be involved in AIP-SC. The latter is a distinct clinicopathological entity that should be distinguished from PSC because it responds well to steroid therapy.

Corticosteroid-responsive pancreatic cyst found in autoimmune pancreatitis

There have been only a few reports of autoimmune pancreatitis complicated with pancreatic cyst and such cysts are rare, probably due to the absence of severe tissue necrosis and/or lack of stasis of the pancreatic juice in this condition. However, during a follow-up of 48 patients with this disease, we found 3 patients with pancreatic cysts, and this enabled us to evaluate their clinicopathological findings. Between September 1994 and July 2003, we treated and followed 48 patients with autoimmune pancreatitis, and found 3 patients with pancreatic cyst formation that was responsive to corticosteroid therapy. All of the patients with cysts had high serum IgG4 concentrations. After corticosteroid therapy, rapid resolution of the pancreatic cysts was observed. Immunostaining with goat polyclonal antibody for each IgG subclass showed severe infiltration of IgG4-positive plasma cells in the cyst wall in one patient. The high serum IgG4 concentration and favorable response to corticosteroid therapy suggests that a highly active state of the inflammatory process is closely associated with cyst formation, and that a corticosteroid-responsive pancreatic cyst is a characteristic feature of autoimmune pancreatitis.

High prevalence of hypothyroidism in patients with autoimmune pancreatitis

Autoimmune pancreatitis is a unique form of chronic pancreatitis and has been correlated with various extrapancreatic lesions. To search for a correlation between autoimmune pancreatitis and thyroid lesions, we measured thyroid functions in 41 patients with autoimmune pancreatitis and in 41 patients with chronic calcifying pancreatitis and investigated the correlation between HLA antigens and hypothyroidism. We found a significant difference in the prevalence of antithyroglobulin antibody and hypothyroidism between patients with autoimmune pancreatitis and those with chronic pancreatitis (34.1 vs. 7.3%, P = 0.005, and 26.8 vs. 0%, P = 0.0005, respectively). Patients with hypothyroidism had a significantly higher frequency of antithyroglobulin antibody (63.6%) than those without hypothyroidism but showed no differences in other findings, including serum IgG4 concentration. We could find no significant association between any HLA antigens and the hypothyroid state of autoimmune pancreatitis. One quarter of the patients with autoimmune pancreatitis have hypothyroidism that may be independent of the active state of the pancreatic lesion or systemic fibrosing disorder, and thus patients suspected of having autoimmune pancreatitis should be evaluated for possible hypothyroidism.

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.

Recurrent attacks of autoimmune pancreatitis result in pancreatic stone formation

OBJECTIVES

Autoimmune pancreatitis has been characterized by irregular narrowing of the main pancreatic duct and sonolucent swelling of the parenchyma, both of which are due to lymphoplasmacytic inflammation at the active stage of the disease, and by the absence of pancreatic stone formation. The aim of the present study was to confirm or deny whether or not this disease is progressive with recurrent attacks, resulting in pancreatic stone formation like ordinary chronic pancreatitis.

METHODS

Forty-two patients, 36 of whom were treated with prednisolone, were followed up for periods longer than 12 months (median follow-up period: 54.5 months, range: 13-111 months) by regular interview and examination of their medical records for laboratory tests and image tests.

RESULTS

Eleven patients (26.2%) who were treated with prednisolone showed recurrent attacks during median follow-up periods of 22 months. Eight patients (19%) showed the formation of pancreatic stones during the follow-up periods. Because 6 of 11 patients (54.5%) who suffered relapse showed pancreatic stone formation, it is significantly associated with relapse in comparison with nonrelapse (p= 0.0019).

CONCLUSIONS

Contrary to previous reports, we observed both relapse and pancreatic stone formation in some patients with autoimmune pancreatitis, which suggests that autoimmune pancreatitis has the potential to be a progressive disease with pancreatic stones.

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.

Hilar and pancreatic gallium-67 accumulation is characteristic feature of autoimmune pancreatitis

INTRODUCTION AND AIMS

Autoimmune pancreatitis is characterized by severe lymphocytic inflammation, suggesting that gallium-67 scintigraphy provides a useful tool for detecting characteristic lesions of this disease, because gallium-67 concentrates in lymphoid cells. We tried to determine whether gallium-67 accumulates in the characteristic lesions.

METHODOLOGY

We performed gallium-67 scintigraphy in 24 patients with autoimmune pancreatitis before and after 4 weeks of corticosteroid therapy and determined the factors associated with positive images.

RESULTS

Sixteen patients (67%) had marked gallium-67 accumulation in the pancreas before corticosteroid therapy and negative images after 4 weeks of therapy, and they had significantly higher serum IgG4 values than did those without gallium-67 accumulation (median, 758 mg/dL versus 329 mg/dL; p = 0.011). Marked hilar gallium-67 accumulation was found in 16 patients (67%) and was also associated with significantly higher serum IgG4 values than did those without it (median, 758 versus 239 mg/dL; p = 0.0044). Among 16 patients with positive hilar images, 12 had positive pancreatic uptake and 5 had both pancreatic and salivary gland uptakes.

CONCLUSIONS

Hilar and pancreatic accumulation of gallium-67 is a characteristic feature of autoimmune pancreatitis during the active stage of the disease, when IgG4 serum levels are high.

Clinical study of chronic pancreatitis with focal irregular narrowing of the main pancreatic duct and mass formation: comparison with chronic pancreatitis showing diffuse irregular narrowing of the main pancreatic duct

INTRODUCTION

Main pancreatic duct (MPD)-narrowed chronic pancreatitis (CP) may be an autoimmune abnormality. It also has been called autoimmune pancreatitis and sclerosing pancreatitis. It is unclear whether cases with focal pancreatographic changes are part of the same clinical entity as cases with diffuse MPD changes.

AIM AND METHODOLOGY

We reviewed seven cases of chronic pancreatitis (CP) with focal narrowing of the main pancreatic duct (MPD), evidenced by endoscopic retrograde cholangiopancreatography (ERCP), and swelling of one or two segments of the pancreas, evidenced by ultrasonography (US) /computed tomography (CT), and indicated the clinicopathologic features of focal-type MPD-narrowed CP.

RESULTS

The patient group comprised six men and one woman, and their age range was 28-75 years, with a mean of 63.7 years. Affected sites were in the head in two patients, the body in one patient, the tail in one patient, and the body and tail in three patients; ERP showed narrowing in six patients and obstruction in one. Stricture of the lower portion of the common bile duct (CBD) that caused obstructive jaundice was shown by ERC in two cases in which the pancreas head was affected. In all six patients, a dynamic study by CT or MRI homogeneously showed delayed enhancement of involved segments of the pancreas. Serum levels of pancreatic enzyme were elevated in five patients, but only one subject had pancreatitis-like epigastric pain. Serological evidence suggestive of autoimmune abnormality was detected in only three patients with hypergammaglobulinemia (> or =2.0 g/dL) or positive titers of antinuclear antibody (ANA; > or =80). Histological assessment was available for five patients, who characteristically had dense lymphocytic or plasmocytic infiltration with severe fibrosis that caused luminal narrowing. The clinical, serologic, and histologic findings as described above were comparable to those for 12 CP patients with diffuse narrowing of the MPD, diagnosed during the same period. Surgical resection was performed in 5 patients, in 2 of whom a similar inflammatory process recurred in the remnant head of the pancreas, whereas pancreatitis no longer developed in the other 3 patients. One patient was initially treated with steroids, with clinical remission, although there was neither hypergammaglobulinemia nor positive ANA.

CONCLUSION

These results indicate that CP with focal narrowing of the MPD is part of the same clinical spectrum as CP with diffuse narrowing of the MPD, and whether the distribution is diffuse or focal seems to be related to the stage or the extent of the disease. It is therefore important to recognize the possible existence of this focal variant to avoid unnecessary surgery.

High serum IgG4 concentrations in patients with sclerosing pancreatitis

BACKGROUND

Sclerosing pancreatitis is a unique form of pancreatitis that is characterized by irregular narrowing of the main pancreatic duct, lymphoplasmacytic inflammation of the pancreas, and hypergammaglobulinemia and that responds to glucocorticoid treatment. Preliminary studies suggested that serum IgG4 concentrations are elevated in this disease but not in other diseases of the pancreas or biliary tract.

METHODS

We measured serum IgG4 concentrations using single radial immunodiffusion and an enzyme-linked immunosorbent assay in 20 patients with sclerosing pancreatitis, 20 age- and sex-matched normal subjects, and 154 patients with pancreatic cancer, ordinary chronic pancreatitis, primary biliary cirrhosis, primary sclerosing cholangitis, or Sjögren's syndrome. Serum concentrations of immune complexes and the IgG4 subclass of immune complexes were determined by means of an enzyme-linked immunosorbent assay with monoclonal rheumatoid factor.

RESULTS

The median serum IgG4 concentration in the patients with sclerosing pancreatitis was 663 mg per deciliter (5th and 95th percentiles, 136 and 1150), as compared with 51 mg per deciliter (5th and 95th percentiles, 15 and 128) in normal subjects (P<0.001). The serum IgG4 concentrations in the other groups of patients were similar to those in the normal subjects. In patients with sclerosing pancreatitis, serum concentrations of immune complexes and the IgG4 subclass of immune complexes were significantly higher before glucocorticoid therapy than after four weeks of such therapy. Glucocorticoid therapy induced clinical remissions and significantly decreased serum concentrations of IgG4, immune complexes, and the IgG4 subclass of immune complexes.

CONCLUSIONS

Patients with sclerosing pancreatitis have high serum IgG4 concentrations, providing a useful means of distinguishing this disorder from other diseases of the pancreas or biliary tract.