BACKGROUND: The risk and prognosis of pancreatobiliary cancer and in patients with autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-SC) remain unclear. Therefore, we retrospectively investigated the risk of pancreatobiliary cancer and prognosis in patients with AIP and IgG4-SC.
METHODS: Patients with AIP and IgG4-SC at seven centers between 1998 and 2022 were investigated. The following data were evaluated: (1) the number of cancers diagnosed and standardized incidence ratio (SIR) for pancreatobiliary and other cancers during the observational period and (2) prognosis after diagnosis of AIP and IgG4-SC using standardized mortality ratio (SMR).
RESULTS: This study included 201 patients with AIP and IgG4-SC. The mean follow-up period was 5.7 years. Seven cases of pancreatic cancer were diagnosed, and the SIR was 8.11 (95% confidence interval [CI]: 7.29-9.13). Three cases of bile duct cancer were diagnosed, and the SIR was 6.89 (95% CI: 6.20-7.75). The SMR after the diagnosis of AIP and IgG4-SC in cases that developed pancreatobiliary cancer were 4.03 (95% CI: 2.83-6.99).
CONCLUSIONS: Patients with autoimmune pancreatitis and IgG4-SC were associated with a high risk of pancreatic and bile duct cancer. Patients with AIP and IgG4-SC have a worse prognosis when they develop pancreatobiliary cancer.

OBJECTIVE: The acceptable duration of steroid therapy for patients with IgG4-sclerosing cholangitis (SC) has been under debate. Our aim is to clarify the feasible duration of steroid treatment.
METHODS: We retrospectively reviewed the data of patients with IgG4-SC and analyzed the following: biliary status during the steroid therapy, incidence of remission, relapse, relapse-free survival rate, and steroid-related complications (SRCs).
RESULTS: Remission was achieved 99.5% (763/767) of patients who received steroid therapy, while remission rate dropped to 63.6% (78/129) of patients who didn\'t receive it. Relapse was noted in 19.7% (151/763) of the patients who received steroid. Besides, relapse rate went up 38.4% (30/78) of the counterpart. Normalization of the serum total bilirubin and serum alkaline phosphatase (ALP) levels were achieved at two weeks regardless of biliary drainage. Multivariate analysis identified younger onset, MST less than three years, immunosuppressant, and steroid cessation as independent risk factors for relapse. Steroid-free was achieved in the patients underwent MST only 3.4% over 54 months. SRCs were recorded in a total of 99 patients (12.9%) despite sufficient preemptive medications. Multivariate analysis identified history of malignancy and immunosuppressant as independent risk factors for SRCs.
CONCLUSIONS: Steroid therapy should be continued for no less than three years to reduce the risk of relapse, with use of preemptive measures taken around five years. The biliary drainage might not be mandatory. Steroid as 1st line therapy could serve as a bridge to further promising treatments.

BACKGROUND: In the diagnosis of IgG4-related sclerosing cholangitis (IgG4-SC), differentiation from extrahepatic cholangiocarcinoma (ECC) is extremely important but is still a clinical challenge. This study aimed to elucidate the usefulness of peroral cholangioscopy (POCS) for the differential diagnosis between IgG4-SC and ECC.
METHODS: POCS findings for bile duct stricture were retrospectively evaluated in 17 patients with IgG4-SC diagnosed at the Hiroshima University Hospital and 53 patients with surgically resected infiltrating ECC. Mucosal surface, dilated vessels (tortuosity, caliber alteration, and disruption), and easily bleeding were compared between the groups.
RESULTS: The stricture sites of IgG4-SC evaluated by POCS were 10 extrapancreatic bile ducts and 9 intrapancreatic bile ducts. In patients with IgG4-SC, smooth mucosal surface was observed in 89% (17/19), dilated vessels in 58% (11/19) [tortuosity 82% (9/11), caliber alteration 18% (2/11), and disruption 9% (1/11)], and easily bleeding in 0%. Irregular mucosal surface and easily bleeding were observed significantly more frequently in ECC (both P <  0.001). The frequency of caliber alteration and disruption of dilated vessels was significantly less in IgG4-SC (P <  0.001 and 0.005, respectively). The sensitivity and specificity of POCS in the diagnosis of ECC were 96 and 89%, respectively. Dilated vessels in IgG4-SC were observed significantly more frequently in the extrapancreatic bile duct, especially the hilar bile duct (P = 0.006). Concerning image evaluation, the interobserver agreement was κ = 0.719, and the intraobserver agreement was κ = 0.768 and 0.754.
CONCLUSIONS: Characteristic POCS findings of the stricture sites in IgG4-SC were smooth mucosal surface, dilated vessels without caliber alteration and disruption, and lack of easily bleeding. These POCS findings are extremely useful for distinguishing between IgG4-SC and ECC.

OBJECTIVE: Autoimmune pancreatitis is an autoimmune disorder accompanied by clinicopathological manifestations that have been established as immunoglobulin (IgG)4-related diseases (IgG4-RD). Other IgG4-RD are often involved with autoimmune pancreatitis. They sometimes relapse despite a favorable response to steroid therapy. This study aimed to clarify the patterns and risk factors for extrapancreatic relapse.
METHODS: We reviewed the data of 115 patients diagnosed with definite autoimmune pancreatitis type 1 and followed up for > 1 year. We analyzed two items: the timing and pattern of extrapancreatic relapse, and risk factors for relapse with three common manifestations: IgG4-related sclerosing cholangitis (SC), IgG4-related dacryoadenitis and sialadenitis (DS), and IgG4-related retroperitoneal fibrosis (RF).
RESULTS: Remission was achieved in all patients, except one. The extrapancreatic relapse rates were 11.0%, 19.7%, and 40% within 3, 5, and 10 years, respectively. Of 26 patients with extrapancreatic relapse, nine (34.6%) relapsed with a new IgG4-RD. Based on multivariate analysis, the interval between symptom onset and steroid initiation, and the presence of RF at onset were significant risk factors for relapse with SC and RF, respectively.
CONCLUSIONS: Our results indicate that they may be various extrapancreatic relapse patterns especially in autoimmune pancreatitis with other organ involvement. Patients with a delayed initiation of steroids or RF at onset should be carefully followed up as high-risk groups for SC and RF relapse.