Incidence of the focal type of autoimmune pancreatitis in chronic pancreatitis suspected to be pancreatic carcinoma: experience of a single tertiary cancer center

A solid pancreatic mass: tumour or inflammation?

The prognosis for pancreatic cancer is poor, and early diagnosis is essential for surgical management. By comparison with its classic form, the presence of acute or chronic inflammatory signs will hinder its detection and delay its diagnosis. The atypical forms of acute pancreatitis need to be known in order to detect patients who require additional morphological investigations to search for an underlying tumour. In contrast, pseudotumoral forms of inflammation (chronic pancreatitis, cystic dystrophy in heterotopic pancreas, autoimmune pancreatitis) may simulate a cancer, and make up 5-10% of the surgical procedures for suspected cancer. Faced with these pseudotumoral masses, interpretation relies on various differentiating signs and advances in imaging.

Long-term surgical outcomes of patients with type 1 autoimmune pancreatitis. World J Surg. 2013;37:162-168. [PMID: 23010699 DOI: 10.1007/s00268-012-1803-x]

BACKGROUND

Although pancreatectomy has sometimes been performed for patients with autoimmune pancreatitis (AIP) presenting atypical radiologic findings under the diagnosis of pancreatobiliary malignancy, the long-term surgical outcome of these patients had not yet been fully elucidated.

METHODS

The long-term surgical outcomes of 13 patients with pathologically diagnosed type 1 AIP with immunohistochemical staining for immunoglobulin G4 (IgG4) were retrospectively compared with those of 34 patients with conventional chronic pancreatitis to evaluate the residual pancreatic function.

RESULTS

A definite relapse of AIP in terms of the clinical manifestations and diagnostic imaging was not found in any of the patients, although one patient experienced an attack of acute pancreatitis caused by pancreatic stones, and stricture of the hepaticojejunostomy occurred in one patient. The overall body weight decreased significantly more in patients with AIP than in patients with conventional chronic pancreatitis (p < 0.05); however, there was no difference in the preoperative nondiabetic patients. Refractory diarrhea occurred in only one patient with AIP. The cumulative new-onset rates of diabetes mellitus of the ten patients with AIP and 24 patients with conventional chronic pancreatitis at 5 years after the surgery were 32.5 and 26.1 %, respectively (p = 0.70).

CONCLUSIONS

Careful long-term follow-up is needed for patients undergoing pancreatectomy for type 1 AIP because remnant pancreatic function can deteriorate as severely as that of patients who undergo pancreatectomy for conventional chronic pancreatitis. In the present series, however, there were few definite manifestations indicating relapse or the persistent existence of AIP.

Novel quantitative perfusion analysis with contrast-enhanced harmonic EUS for differentiation of autoimmune pancreatitis from pancreatic carcinoma

OBJECTIVE

Autoimmune pancreatitis (AIP) is often misdiagnosed as pancreatic carcinoma (PC) despite recent advances in imaging tests. The aim of the study was to evaluate whether the quantitative perfusion analysis using software "Time intensity curve" with contrast-enhanced harmonic EUS (CH-EUS) facilitate the differentiation of AIP from PC.

METHODS

Consecutive patients with focal AIP and pancreatic carcinoma who underwent CH-EUS from January 2009 to September 2010 were analyzed. CH-EUS was performed with intravenous administration of an ultrasonographic contrast (Sonazoid) and electronic radial echoendoscope. The graph of time intensity curve (TIC) for pancreatic mass was generated to depict the changes in signal intensity over time within the region of interest (ROI). ROI was placed to cover an area with a pancreatic mass lesion. Based on the analysis of TIC, base intensity before injection (BI), peak intensity (PI), time to peak, and maximum intensity gain (MIG: PI-BI) were calculated.

RESULTS

Eight patients with focal AIP and twenty-two patients with PC were evaluated by TIC. PI and MIG of mass lesion of AIP were significantly higher than that of PC (21.4 dB vs. 9.6 dB, 17.5 vs. 6.6). Receiver operating characteristics analysis yielded an optimal MIG cutoff value of 12.5 with high sensitivity and specificity.

CONCLUSION

Pancreatic mass lesions of AIP and PC exhibited markedly different patterns with the TIC. This novel diagnostic modality using TIC generated by CH-EUS might offer an opportunity to improve accuracy in the differential diagnosis between pancreatic mass lesion of AIP and PC.

A practical approach to the diagnosis of autoimmune pancreatitis

Autoimmune pancreatitis is a disease characterized by specific pathological features, different from those of other forms of pancreatitis, that responds dramatically to steroid therapy. The pancreatic parenchyma may be diffusely or focally involved with the possibility of a low-density mass being present at imaging, mimicking pancreatic cancer. Clinically, the most relevant problems lie in the diagnosis of autoimmune pancreatitis and in distinguishing autoimmune pancreatitis from pancreatic cancer. Since in the presence of a pancreatic mass the probability of tumour is much higher than that of pancreatitis, the physician should be aware that in focal autoimmune pancreatitis the first step before using steroids is to exclude pancreatic adenocarcinoma. In this review, we briefly analyse the strategies to be followed for a correct diagnosis of autoimmune pancreatitis.

Diagnosis and treatment of autoimmune pancreatitis

PURPOSE OF REVIEW

To summarize the existing knowledge of autoimmune pancreatitis (AIP) and to review the progress made in the diagnosis and treatment of AIP in the past year.

RECENT FINDINGS

The term 'AIP' appears to encompass at least two distinct subtypes, type 1 and type 2. Type 1 AIP is the pancreatic manifestation of a systemic fibroinflammatory disease called immunoglobulin G4-associated systemic disease. Type 2 AIP affects younger patients, does not have a gender predilection and is associated with normal serum immunoglobulin G4 levels. Existing criteria are geared toward diagnosis of type 1; type 2 AIP can be definitively diagnosed only on pancreatic histology. Both subtypes respond to corticosteroid therapy. However, there are no standardized protocols for initial treatment or management and prevention of relapses in AIP. A novel antibody for AIP has recently been identified and its performance needs validation from other centers. Newly published strategies for differentiating AIP from pancreatic cancer are available.

SUMMARY

AIP is a rare disease whose recognition and understanding are evolving. Much needs to be elucidated with regard to its cause, pathogenesis, treatment of relapse and long-term outcomes. A multidisciplinary team, familiar with the disease, is critical in making the correct diagnosis.

Autoimmune pancreatitis

BACKGROUND

Autoimmune pancreatitis (AIP) is a relatively newly recognized type of pancreatitis that is characterized by diffuse or focal swelling of the pancreas due to lymphoplasmacytic infiltration and fibrosis of the pancreatic parenchyma.

MATERIAL AND METHODS

A PubMed literature search was performed using the keywords "autoimmune pancreatitis". Sometimes, bibliographies were cross-referenced and related article searches were performed once an article of interest was identified.

RESULTS

Pathologically, AIP shows narrowing of the pancreatic ducts and the intrapancreatic portion of the common bile duct. Obstructive jaundice is a common symptom at presentation, and pancreatic cancer represents an important clinical differential diagnosis. In late stages of the disease, the normal pancreatic parenchyma is often replaced by large amounts of fibrosis. Histologically, there seem to be two subtypes of the disease-one showing infiltration with IgG4-positive plasma cells but lacking granulocytic epithelial lesions (GELs), the other showing GELs but lacking strong IgG4 positivity. AIP is in at least some instances the pancreatic manifestation of a clinicopathological entity of IgG4-related systemic sclerosing disease. On the basis of pancreatic imaging, together with serological measurement of IgG4 and evaluation of other organ involvement, many AIP patients can be identified. The remaining patients require further diagnostic work-up. In these patients, pancreatic core needle biopsy and, as AIP responds to steroid treatment, also a trial with steroids, can help to differentiate AIP from pancreatic cancer. OUTLOOK AND DISCUSSION: This review presents the pathological, radiologic and laboratory findings of AIP. Moreover, the treatment and pathogenesis are discussed.

Incidence, clinical presentation and pathological features of benign sclerosing cholangitis of unknown origin masquerading as biliary carcinoma

BACKGROUND

Benign obstructions of the liver hilum are occasionally encountered in surgically resected cases. Some of these cases are pathologically classified as benign sclerosing cholangitis and are not clearly categorized. This study aims to elucidate the clinicopathological features of benign sclerosing cholangitis of unknown origin.

METHODS

Patients who had undergone surgery of the proximal bile duct from 1993 to 2008 on suspicion of proximal bile carcinoma were evaluated, then their clinical presentation, histopathological and immunohistochemical findings were retrospectively analyzed.

RESULTS

One hundred seventy-six patients underwent surgery during this period. Of these, five patients were diagnosed with benign sclerosing cholangitis of unknown origin. All five patients were middle-aged with no history of autoimmune disease. One patient died of recurrent cholangitis after surgery. Histopathologically, lymphoplasmacytic infiltrations were observed in all five cases. Among them, the clinicopathological findings of one patient were compatible with IgG4-related sclerosing cholangitis, and the other two patients had unusual histopathological findings with prominent lymph follicular formation.

CONCLUSIONS

Although patients with benign sclerosing cholangitis of unknown origin comprise a heterogeneous population, they can be further classified into subgroups. The response to immunosuppressive therapy, long-term prognosis and histological morphology of the disease should be considered in order to classify these cases of sclerosing cholangitis.

A case of pancreatic carcinoma with suspected autoimmune pancreatitis. Clin J Gastroenterol. 2009;2:59-63. [PMID: 26191812 DOI: 10.1007/s12328-008-0045-9]

We present a case of pancreatic carcinoma with strongly suspected coexisting autoimmune pancreatitis (AIP). The patient presented with a chief complaint of icterus and weight loss, and was referred to our institution after a pancreatic lesion was found. Blood test showed elevation of serum bilirubin, hepato-biliary enzyme, glucose and tumor markers, and also high levels of serum IgG4 (344 mg/dl, normal 4.8-105 mg/dl) and anti-DNA antibody (14 IU/ml, normal <6.0 IU/ml). Ultrasonography demonstrated an enlarged pancreas with smooth borders and low internal echo density. Enhanced computed tomography (CT) showed a sausage-shaped pancreas without definitive metastasis to the surrounding lymph nodes and liver. Imaging of the pancreatic duct, including endoscopic retrograde pancreatography (ERP) and magnetic resonance cholangiopancreatography (MRCP), showed stenosis of the main pancreatic duct at the pancreatic head as well as a long segment of narrowing at the body and no dilatation at the tail. Tissues from these stenotic sites and open biopsy from pancreatic body showed infiltrating adenocarcinoma and dense fibrosis. To date, only a small number of reports have described pancreatic carcinoma accompanied with AIP. It is important to confirm diagnosis with histology in cases of suspicious autoimmune pancreatitis, even when the clinical images are compatible with AIP.

Autoimmune pancreatitis

PURPOSE OF REVIEW

Autoimmune pancreatitis (AIP) is an increasingly recognized clinical condition. Our objective is to provide a concise review of the advances in the past year in our understanding of AIP.

RECENT FINDINGS

In a hospital survey from Japan, the prevalence of AIP was estimated at 0.82 per 100,000 individuals. The pathogenesis of AIP remains unclear but a recent report noted that T helper type 2 and T regulatory cells predominantly mediate the immune reaction in AIP. Genetic associations that may predispose to relapse of AIP were reported. Multiple case series further described the clinical profile of AIP and its extrapancreatic manifestations. A large series on immunoglobulin G4 (IgG4)-associated cholangitis noted that patients with IgG4-associated cholangitis presented with obstructive jaundice and had increased serum IgG4 levels and IgG4-positive cells in bile duct biopsy specimens. Tissue IgG4 staining is likely to be a useful adjunct to serological diagnosis. AIP is steroid-responsive but maintaining remission continues to remain challenging. Presently low-dose steroids or immunomodulators are being used but efficacy of these medications remains to be determined.

SUMMARY

There has been significant progress in understanding the clinical profile of AIP but knowledge of pathogenesis remains limited. Treatment practices vary widely and management of refractory disease continues to be challenging.