Differentiation between autoimmune pancreatitis and pancreatic carcinoma based on endoscopic retrograde cholangiopancreatography findings.

OBJECTIVE: We have reviewed the endoscopic retrograde cholangiopancreatography (ERCP) images of patients with autoimmune pancreatitis (AIP) and pancreatic carcinoma (Pca) in an attempt to identify findings that would facilitate making a differential diagnosis between AIP and Pca. METHODS: The study cohort consisted of 39 patients diagnosed with AIP and 62 patients diagnosed with Pca. The ERCP findings in the pancreatic duct and biliary tract were compared between the two groups. RESULTS: The ERCP images revealed that AIP patients had a higher prevalence of narrowing of the main pancreatic duct (MPD) for ≥ 3 cm of its length and a higher prevalence for the presence of side branches in the narrowed portion of the MPD than Pca patients (p < 0.001 and p < 0.001, respectively). In contrast, the prevalence of an upstream MPD having a maximal diameter ≥ 4 cm was significantly higher in the Pca patient group (p < 0.001). The discriminant analysis identified three significant factors: (1) whether or not side branches were present; (2) total length of the narrowed portion of the MPD; (3) maximal diameter of the upstream MPD. It was impossible to differentiate Pca from AIP in the two Pca patients in whom ERCP revealed both narrowing of the MPD for > 5 cm of its length and the presence of side branches. CONCLUSIONS: Among our patient cohort, the ERCP findings in terms of the length of the narrowed portion of the MPD, the presence of side branches, and maximal diameter of the upstream MPD enabled differential diagnosis between AIP and Pca in most of the cases. However, it must be borne in mind that some Pca patients have ERCP findings similar to those of AIP patients.

Clinicopathological differentiation between sclerosing cholangitis with autoimmune pancreatitis and primary sclerosing cholangitis.

BACKGROUND: The present study was undertaken to identify the clinicopathological differences between sclerosing cholangitis with autoimmune pancreatitis (SC-AIP) and primary sclerosing cholangitis (PSC). METHODS: We retrospectively compared the clinical, cholangiographic, and liver biopsy findings between 24 cases of PSC and 24 cases of SC-AIP. RESULTS: Patient age at the time of diagnosis was significantly lower in the PSC group than in the SC-AIP group. The peripheral blood eosinophil count was significantly higher in the PSC group than in the SC-AIP group, but the serum IgG4 level was significantly higher in the SC-AIP group. Cholangiography revealed band-like strictures, beaded appearance, and pruned-tree appearance significantly more frequently in PSC, whereas segmental strictures and strictures of the distal third of the common bile duct were significantly more common in SC-AIP. Liver biopsy revealed fibrous obliterative cholangitis only in the PSC specimens. No advanced fibrous change corresponding to Ludwig's stages 3 and 4 was observed in any of the SC-AIP specimens. IgG4-positive plasma cell infiltration of the liver was significantly more severe in SC-AIP than in PSC. Subsequent cholangiography showed no improvement in any of the PSC cases, but all SC-AIP patients responded to steroid therapy, and improvement in the strictures was observed cholangio-graphically. CONCLUSIONS: Based on the differences between the patients' ages and blood chemistry, cholangiographic, and liver biopsy findings, SC-AIP should be differentiated from PSC.

Prevalence of pancreatic and biliary tract tumors in pancreas divisum.

BACKGROUND: The present study was undertaken to evaluate the prevalence of pancreatic and biliary tract tumors in pancreas divisum (PD). METHODS: A retrospective single-center study was performed, and a total of 118 cases of complete PD and 7850 cases of fused pancreas were identified among the 8537 consecutive new endoscopic retrograde cholangiopancreatography (ERCP) examinations performed between 1980 and 2002. The prevalence of pancreatic cancer (PCA), intraductal papillary mucinous neoplasms (IPMNs), other pancreatic tumors, and biliary tract cancer in the patients with PD and the patients with a fused pancreas were compared. RESULTS: The prevalence of the pancreatic tumors in the PD patients was: PCA, 10%; IPMN, 5.1%; other pancreatic tumors, 2.5%. The prevalence of pancreatic tumors in the patients with a fused pancreas was: PCA, 4.8%; IPMN, 2.6%; and other pancreatic tumors, 1.1%. The prevalence of PCA was significantly higher in the patients with PD than in those with a fused pancreas (P = 0.008; OR, 2.24). The percentages of PD patients with PCA who had pancreatic-type pain and a serum pancreatic enzyme elevation were significantly higher than among the PD patients without PCA. The prevalence of biliary tract cancer was 0.8% in the PD group and 5.3% in the fused pancreas group, and it was significantly lower in PD than in fused pancreas (P = 0.031). CONCLUSIONS: The results of this study showed a significantly higher prevalence of PCA in PD than in fused pancreas. We concluded that patients with PD, especially patients presenting with pancreatic-type pain and pancreatic enzyme elevation, should be carefully followed up because of the risk of developing PCA.

Long-term outcome of autoimmune pancreatitis after oral prednisolone therapy.

OBJECTIVE: We investigated the long-term outcome of autoimmune pancreatitis (AIP) including morphological changes in the pancreas, pancreatic duct, biliary tract, pancreatic function, and changes in the clinical manifestations after oral prednisolone (PSL) therapy. PATIENTS AND METHODS: We prospectively followed 12 patients for a period of over 12 months (median follow-up period: 41 months; range: from 13 to 133 months). All twelve patients were treated with PSL. The morphological findings consisted of pancreatic enlargement (n=12), an irregularly narrowed main pancreatic duct (n=12), and bile duct stricture (n=10), and salivary gland swelling was observed in six patients. The initial dose of PSL was 30-40 mg/day, and it was subsequently tapered. RESULTS: All 12 patients responded to PSL therapy. The enlargement of the pancreas and the irregularly narrowed main pancreatic duct improved to almost normal. Pancreatic atrophy developed in four of them (4/12, 33%), but no pancreatic calcification was observed in any of the patients. The bile duct stricture improved to various degrees in all 10 patients , but it persisted in the lower part of the bile duct in four of them (4/10, 40%). The salivary gland swelling also improved after PSL therapy. There was no recurrence of enlargement of the pancreas or irregularly narrowed main pancreatic duct after PSL therapy, but the bile duct stricture recurred in one case, and in three cases there was a relapse of salivary gland swelling that required a temporary increase in PSL dose during tapering. No deterioration of pancreatic exocrine function was detected in any of the patients. A malignant tumor was diagnosed in two patients during PSL therapy: early gastric cancer in one and rectal cancer in the other. All patients are alive. CONCLUSIONS: AIP treated with PSL has a favorable long-term outcome based on the morphological findings and assessments of pancreatic function. However, since two of the twelve patients developed a malignancy during PSL therapy, strict follow up should be part of the management of AIP.

Biliary tract involvement in autoimmune pancreatitis.

OBJECTIVES: Autoimmune pancreatitis (AIP) is a unique clinical entity that has been recently proposed, and it is frequently associated with bile duct stricture. The aim of this study was to investigate the pathophysiology of the biliary tract involvement in patients with AIP. METHODS: We evaluated the clinicopathologic findings in 16 patients with AIP. Surgical resection was performed in 7 of the patients because of suspicion of a pancreatic tumor; 8 of the other patients were treated with oral prednisolone (PSL) therapy, and the remaining patient was observed clinically and not treated. The pancreas, bile duct, and gallbladder in the surgical cases were examined histologically and immunohistochemically. We also assessed the clinical manifestations and diagnostic imaging findings before and after oral PSL therapy in the 8 patients treated with PSL. RESULTS: Stricture of the extrahepatic bile duct was detected in 88% (14/16) of the patients. Thickening of the bile duct wall was detected in 94% (15/16), and thickening of the gallbladder wall was observed in 56% (9/16). Histologically, the bile duct and gallbladder wall were characterized by diffuse lymphoplasmacytic infiltration and marked interstitial fibrosis. Immunohistochemically, the diffusely infiltrating cells consisted of predominantly CD8- or CD4-positive T lymphocytes and IgG4-positive plasma cells. These findings were the same as in the inflammatory process that was observed in the pancreas. After oral PSL therapy, the pancreatic enlargement and irregular narrowing of the main pancreatic duct improved to almost their normal size in all 8 patients; however, stricture of the extrahepatic bile duct persisted in 4 of the patients (57%, 4/7) in whom it was detected before PSL therapy. CONCLUSIONS: Based on the pathophysiologic and histologic findings and the response to PSL therapy, the biliary involvement in AIP developed by the same mechanism as the pancreatitis. CD8- and CD4-positive lymphocytes and IgG4-positive plasma cells may play an important role in the pathogenesis of AIP.