Mass-forming Autoimmune Pancreatitis Research Articles

Characteristics of mass-forming autoimmune pancreatitis commonly misdiagnosed as a malignant tumor.

This study aimed to explore the clinical characteristics and differential diagnosis of patients with autoimmune pancreatitis (AIP) and pancreatic cancer to prevent misdiagnosis and mistreatment. The clinical data of patients with AIP with suspected pancreatic or bile duct malignancy and pancreatic cancer were retrospectively analyzed. The risk factors and the diagnostic value of IgG4 and Tbil levels before treatment for AIP was investigated. Moreover, the imaging features and response to hormone therapy were analyzed. AIP was commonly observed in men. Compared to patients with pancreatic cancer, the incidence of poor appetite and weight loss and carbohydrate antigen 19-9 (CA19-9) level was lower in patients with AIP, while the immunoglobulin G4 (IgG4) level was higher (p < 0.05). After treatment, the IgG4 and CA19-9 levels in patients with AIP were decreased (p < 0.001). IgG4 level before treatment (OR = 2.452, 95%CI: 1.180-5.096, P = 0.016) and total bilirubin (Tbil) level before treatment (OR = 0.992, 95%CI: 0.985-0.998, P = 0.013) were independent risk factors of AIP. Furthermore, the diagnostic value of IgG4 level before treatment, Tbil level before treatment, IgG4/Tbil before treatment, and a combination of these indicators was high. Moreover, 15 (68.18%) patients with AIP had space-occupying lesions of the pancreas, and 16 (72.73%) had autoimmune cholangitis. Most patients with AIP were sensitive to hormone therapy. The Tbil and IgG4 levels, imaging findings, and hormone therapy reactivity could differentiate AIP from pancreatic cancer. A combination of IgG4, Tbil, and IgG4/Tbil before treatment might be a promising diagnostic biomarker for AIP.

Multimodel magnetic resonance imaging of mass-forming autoimmune pancreatitis: differential diagnosis with pancreatic ductal adenocarcinoma

PurposeTo assess the value of the multimodel magnetic resonance imaging (MRI), including unenhanced images, dynamic contrast-enhanced MRI (DCE-MRI), MR-cholangiopancreatography (MRCP), and diffusion-weighted imaging (DWI), in differentiation of mass-forming autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).MethodsTwelve patients with mass-forming AIP and 30 with PDAC were included. All patients underwent unenhanced MRI, DCE-MRI, DWI, and MRCP. Relevant values including sensitivity and specificity of the imaging features and their diagnostic performance for predicting mass-forming AIP were analyzed.ResultsSeveral statistically significant MR findings and quantitative indexes differentiating mass-forming AIP from PDAC, including multiplicity, irregularity or conformation, capsule-like rim enhancement, absence of internal cystic or necrotic portion, homogeneous enhancement during pancreatic, venous, and delayed phases, skipped stricture or stricture of MPD, absence of side branch dilation, maximum upstream MPD diameter < 2.4 mm, ContrastUP > 0.739, ContrastAP > 0.710, ContrastPP > 0.879, and ContrastVP or ContrastDP > 0.949, indicated mass-forming AIP (P < 0.05). The apparent diffusion coefficient (ADC) value was also significantly lower in mass-forming AIP compared to that in PDAC (P = 0.006). The cutoff value of ADC for distinguishing mass-forming AIP from PDAC was 1.099 × 10−3 mm2/s.ConclusionMultimodel MRI, including unenhanced MRI, DCE-MRI with DWI and MRCP can provide qualitative and quantitative information about mass-forming AIP characterization. Multimodel MRI are valuable for differentiating mass-forming AIP from PDAC.

Effective apparent diffusion coefficient parameters for differentiation between mass-forming autoimmune pancreatitis and pancreatic ductal adenocarcinoma.

To evaluate the diagnostic performance of apparent diffusion coefficient (ADC) parameters by region of interest (ROI) methods in differentiating mass-forming autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC). The institutional review board approved this retrospective study and the requirement for informed consent was waived. Twenty-three patients with mass-forming AIP and 144 patients with PDAC underwent diffusion-weighted imaging with b-values of 0 s/mm2 and 800 s/mm2. The minimum, maximum, and mean ADC values obtained by placing ROIs within lesions and percentile ADC values (10th, 25th, 50th, 75th, and 90th) from entire-lesion histogram analysis were compared between the two groups by using Mann-Whitney U tests. The diagnostic performance was evaluated by receiver operating characteristic (ROC) curve analysis. The minimum, maximum, and mean ADC values were significantly different between mass-forming AIP and PDAC groups. ROC curve analysis showed that the maximum ADC had the highest diagnostic performance (0.92), while the minimum ADC value had the lowest diagnostic performance (0.72). The AUC of minimum ADC was significantly lower than that of maximum or mean ADC (P < 0.0001, P < 0.0001). The AUC was lowest in 10th percentile ADC value and highest in 90th percentile value. The AUC increased along with the increase of percentile values. Either the maximum or mean ADC value was effective in differentiating mass-forming AIP from the PDAC group, while the minimum ADC value might not be recommended.

Differentiating Mass-Forming Autoimmune Pancreatitis From Pancreatic Ductal Adenocarcinoma on the Basis of Contrast-Enhanced MRI and DWI Findings.

The purpose of this study was to assess value of contrast-enhanced MRI, MRCP, and DWI for differentiating mass-forming autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC). This study included 15 patients with mass-forming AIP and 79 with PDAC who underwent gadoxetic acid-enhanced MRI with DWI and MRCP. Two radiologists evaluated the MRI findings in consensus. Statistically significant imaging findings were identified through univariate and multivariate analyses, and their diagnostic performance for predicting mass-forming AIP was analyzed. In the univariate analysis, multiplicity, similar or high signal intensity on portal phase and 3- and 20-minute delayed phase images, homogeneous enhancement, no peripancreatic fat infiltration, no internal cystic or necrotic portion, capsulelike rim, no upstream pancreatitis, no vascular invasion, and duct penetrating sign were more frequently observed (p < 0.05) in mass-forming AIP. The apparent diffusion coefficient (ADC) value was also significantly lower for mass-forming AIP than for PDAC (0.96 ± 0.14 versus 1.13 ± 0.23 × 10(-3) mm(2)/s; p < 0.001). The optimal cutoff value of ADC for differentiating mass-forming AIP from PDAC was 0.9407 × 10(-3) mm(2)/s. In multivariate analysis, homogeneous enhancement (p = 0.001), duct penetrating sign (p < 0.001), and ADC value less than 0.9407 × 10(-3) mm(2)/s (p < 0.001) were significant for differentiating mass-forming AIP from PDAC. When two of these three criteria were combined, 80% (12/15) of mass-forming AIPs were identified with specificity of 98.7%. When all three criteria were satisfied, specificity was 100%. Contrast-enhanced MRI with MRCP and DWI may be helpful for differentiating mass-forming AIP from PDAC.

Localized Mass-Forming Autoimmune Pancreatitis Associated with an Intraductal Papillary Mucinous Neoplasm Mimicking Pancreatic Cancer

Localized Mass-Forming Autoimmune Pancreatitis Associated with an Intraductal Papillary Mucinous Neoplasm Mimicking Pancreatic Cancer

Mo1526 EUS Image Based Digital Imaging Processing Technology in the Differentiation of Pancreatic Cancer and Mass Forming Autoimmune Pancreatitis

Mo1526 EUS Image Based Digital Imaging Processing Technology in the Differentiation of Pancreatic Cancer and Mass Forming Autoimmune Pancreatitis

18-Fluorodeoxyglucose Positron Emission Tomography Does Not Aid in Diagnosis of Pancreatic Ductal Adenocarcinoma

There are no accurate and reliable tools for diagnosis of early stage pancreatic ductal adenocarcinoma (PDA) or small metastatic lesions. It is also a challenge to differentiate PDA from focal mass-forming pancreatitis (FMP). There is controversy regarding the efficacy of 18-fluorodeoxyglucose positron-emission tomography (FDG-PET) in the diagnosis of PDA. We investigated whether FDG-PET provides information that, combined with data from other imaging techniques, can aid in decision making for patients with suspected PDA. We performed a retrospective analysis of data collected from 232 consecutive patients with suspected PDA at Kobe University Hospital from January 2006 through June 2012. All patients underwent a diagnostic imaging protocol that included multidetector row computed tomography, superparamagnetic iron oxide-enhanced magnetic resonance imaging, and FDG-PET. Based on endoscopic ultrasonography, fine-needle aspiration biopsy, or endoscopic retrograde cholangiopancreatography analyses, 218 patients had PDA (89 underwent resection and 129 did not) and 14 patients had FMP (8 had focal mass-forming chronic pancreatitis and 6 had focal mass-forming autoimmune pancreatitis). FDG-PET detected 50% of stages 0 and I, 91.9% of stage II, 100% of stage III, and 96.8% of stage IV tumors. Detection was affected significantly by tumor size (P = .024) and T stage (P = .023) in resected tumors. Multidetector row computed tomography detected significantly more liver metastases than FDG-PET. Few para-aortic lymph node or peritoneal metastases were detected by FDG-PET. FDG-PET correctly identified 11 of the 14 patients with FMP (5 of 8 with focal mass-forming chronic pancreatitis and 6 of 6 with focal mass-forming autoimmune pancreatitis). FDG-PET is not effective in detecting early stage PDA and small metastases, or in differentiating PDA from FMP. Combining FDG-PET with current diagnostic techniques for PDA did not provide any decisive information, therefore it should not be included in this analysis.

Differentiation of Mass-Forming Autoimmune Pancreatitis from Pancreatic Cancer Using A 2-Week Steroid Trial

췌장 ì¢ ê´´ë¡œ 발현하는 자가면역 췌장염은 췌장암과의 감별이 매우 중요한데, 이는 ìŠ¤í Œë¡œì´ë“œì— 대한 치료 반응이 매우 좋아 불필요한 ìˆ˜ìˆ ì„ í”¼í• ìˆ˜ 있기 때문이다. 이번 증례에서는 재발성 자가면역 췌장염의 ë³‘ë ¥ì´ 있는 환자에서 발견된 국소 췌장 ì¢ ê´´ 및 상류쪽 주췌관의 확장 소견에 대해 2주간의 경구 ìŠ¤í Œë¡œì´ë“œë¥¼ 투약한 후 복부 CT를 시행한 ê²°ê³¼, 췌장 ì¢ ê´´ì˜ 크기 감소와 주췌관 확장의 í˜¸ì „ì„ 확인하였다. 이를 통해 자가면역 췌장염과 췌장암의 감별 진단에 도움을 얻었다. 이후 ì§€ì†ì ìœ¼ë¡œ 경구 ìŠ¤í Œë¡œì´ë“œë¥¼ 투약하면서 병변이 거의 소실된 것을 í™•ì¸í•˜ì˜€ê³ ìžê°€ë©´ì—­ 췌장염을 í™•ì§„í• ìˆ˜ 있었다. 경구 ìŠ¤í Œë¡œì´ë“œë¥¼ 2주간 투약한 후, 영상 의학 검사를 통한 치료 반응 평가를 통해 ì¢ ê´´ 형성 자가면역 췌장염과 췌장암의 감별 진단에 도움을 얻었던 증례이다. 중심 단어: 자가면역; 췌장염; 췌장암; ìŠ¤í Œë¡œì´ë“œ; ì¢ ê´´

Clinical differences between mass-forming autoimmune pancreatitis and pancreatic cancer

Objective. Autoimmune pancreatitis (AIP) needs to be differentiated from pancreatic cancer (PC). We aimed to clarify the findings specific for AIP by comparing the clinical differences between mass-forming AIP and PC. Material and methods. We retrospectively compared 36 patients with mass-forming AIP and 60 with PC without metastasis regarding clinical, imaging, serological, histological differences and other organ involvement (OOI). We evaluated the sensitivity, specificity and accuracy of these findings for the differential diagnosis between AIP and PC. Results. The findings 100% specific for AIP were a capsule-like rim on computed tomography (CT), skipped lesion of main pancreatic duct (MPD) on endoscopic retrograde pancreatography (ERP) or magnetic resonance cholangiopancreatography (MRCP), γ-globulin > 2 g/dl, OOI (extrapancreatic biliary stricture, salivary gland swelling and retroperitoneal fibrosis) and ruling out PC by histopathological findings of endoscopic ultrasonography-guided fine-needle aspiration. The findings over 90% specific were IgG4 > 280 mg/dl (98%), IgG > 1800 mg/dl (97%), maximal diameter of upstream MPD < 5 mm on MRCP (95%) and IgG4 > 135 mg/dl (94%), respectively. Conclusions. Clinical, imaging, serological, histological findings and OOI differed between mass-forming AIP and PC. Capsule-like rim on CT, skipped lesion of MPD on ERP or MRCP, IgG4 > 280 mg/dl, and OOI were highly specific findings for AIP. These findings are useful in the differential diagnosis of mass-forming AIP from PC.

Magnetic resonance imaging findings of the mass‐forming type of autoimmune pancreatitis: Comparison with pancreatic adenocarcinoma

To determine the characteristic magnetic resonance imaging (MRI) features of mass-forming autoimmune pancreatitis (AIP), which allow its differentiation from pancreatic adenocarcinoma (PAC). MR images of 37 patients with either pathologically proven, mass-forming AIPs (n = 9) or PACs (n = 28) were retrospectively reviewed. The pancreatic MR protocol included unenhanced images, contrast-enhanced dynamic images, diffusion-weighted imaging (DWI), and MR-cholangiopancreatography (MRCP). Two reviewers analyzed the MR images regarding the number, location, morphologic features, and enhancement degree and pattern of the lesions as well as secondary changes of the pancreatic parenchyma, the biliary and pancreatic ducts. The size and apparent diffusion coefficient (ADC) values of the lesions were measured. Although sensitivities were low (28.6%-44.4%), specificities of multiplicity, capsule-like rim enhancement, and skipped stricture of the biliary or pancreatic duct in mass-forming AIP were high (100%). Sensitivities and specificities of irregular or geographic shape, delayed enhancement, and a low ADC value <1.26 × 10(-3) mm(2) /s in mass-forming AIP were favorable (71.4%-83.3% and 78.5%-89.3%). Although to differentiate mass-forming AIP from pancreatic cancer is difficult, the combination of MRI findings including contrast-enhanced dynamic images, MRCP, and DWI can be a help.

Mass‐forming autoimmune pancreatitis and pancreatic carcinoma: Differential diagnosis on the basis of computed tomography and magnetic resonance cholangiopancreatography, and diffusion‐weighted imaging findings

To differentiate mass-forming autoimmune pancreatitis (AIP) from pancreatic carcinoma by means of analysis of both computed tomography (CT) and magnetic resonance imaging (MRI) findings. Ten patients with mass-forming AIP diagnosed by revised clinical criteria of Japan Pancreas Society and 70 patients with pathologically proven pancreatic carcinoma were enrolled in this retrospective study. Two radiologists independently evaluated the CT and MR imaging findings. The sensitivity, specificity, and odds ratio of significant imaging findings and combinations of findings were calculated. Seven findings were more frequently observed in AIP patients: (i) early homogeneous good enhancement, (ii) delayed homogeneous good enhancement, (iii) hypoattenuating capsule-like rim, (iv) absence of distal pancreatic atrophy, (v5) duct penetrating sign, (vi) main pancreatic duct (MPD) upstream dilatation ≤ 4 mm, and (vii) an apparent diffusion coefficient (ADC) ≤ 0.88 × 10(-3) mm(2) /s. When the findings of delayed homogeneous enhancement and ADC ≤ 0.88 × 10(-3) mm(2) /s were both used in diagnosis of mass-forming AIP, a sensitivity of 100% and a specificity of 100% were achieved. When 4 of any of the 7 findings were used in the diagnosis of AIP, a sensitivity of 100% and a specificity of 98% were achieved. Analysis of a combination of CT and MR imaging findings allows for highly accurate differentiation between mass-forming AIP and pancreatic carcinoma.

Mass-forming autoimmune pancreatitis caused after resection of an IgG4-related renal pelvic lesion

Mass-forming autoimmune pancreatitis caused after resection of an IgG4-related renal pelvic lesion

Inflammatory Myofibroblastic Tumor Versus IgG4-related Sclerosing Disease and Inflammatory Pseudotumor

Inflammatory pseudotumor (IPT) is a heterogeneous group of lesions occurring in various organs, which is histologically characterized by fibroblastic and myofibroblastic proliferation with inflammatory infiltrate. Inflammatory myofibroblastic tumor (IMT) is a neoplastic counterpart of IPT, which shows aberrant expression of ALK and its gene translocation. In contrast, the concept "immunoglobulin (Ig)G4-related IPT" in the lung, liver, and pancreas has recently been proposed as a member of IgG4-related sclerosing disease. In this study, we compared the histopathologic features with an emphasis on IgG4 expression between 22 cases of IMT and 16 cases of IgG4-related sclerosing disease, including chronic sclerosing sialadenitis (n=8), mass-forming autoimmune pancreatitis (n=3), sclerosing cholangitis (n=1), retroperitoneal fibrosis (n=2), and chronic sclerosing dacryoadenitis (n=2). Bland-looking spindle cell proliferation with fibrosis and inflammatory infiltrate of lymphocytes and plasma cells was the common morphologic feature in both lesions. Obstructive phlebitis was observed in all of the IgG4-related sclerosing lesions, but in only 1/22 (4.5%) of IMT. The immunohistochemical expression of ALK was observed in 15/22 (68.2%) of IMT and 0/16 (0%) of IgG4-related sclerosing disease. The number of IgG4-positive plasma cells and the ratio of IgG4+/ IgG+ plasma cells were each significantly lower in IMT than in IgG4-related sclerosing disease [mean 6.4/HPF vs. 178.3/HPF (P<0.0001), 3.0% vs. 67.5% (P<0.0001), respectively]. The results suggest that IgG4 does not play an important role in the pathogenesis of IMT. In addition, the evaluation of IgG4+ plasma cells and the ratio of IgG4+/IgG+ plasma cells and the presence of obstructive phlebitis may be useful for the differential diagnosis between IMT and IgG4-related sclerosing disease.

The Clinical and Radiological Characteristics of Focal Mass-Forming Autoimmune Pancreatitis

We investigated the clinical and radiological features of focal mass-forming autoimmune pancreatitis (FMF AIP) to help physicians avoid performing unnecessary surgery because of an improper diagnosis. We evaluated 23 patients with chronic inflammatory pancreatic masses and who underwent pancreatectomy for presumed pancreatic cancer from April 1995 to December 2005. These patients were distinguished into 8 FMF AIP patients and 15 ordinary chronic pancreatitis patients through a histological review, along with considering the immunoglobulin G4 staining. Twenty-six randomly selected pancreatic cancer patients were also evaluated as a control group. On the portal venous phase of computed tomography, 6 (85.7%) of 7 FMF AIP patients showed homogeneous enhancement, whereas only 3 chronic pancreatitis patients (25%) and none of the pancreatic cancer patients showed homogeneous enhancement (P < 0.001). None of the FMF AIP patients showed upstream main pancreatic duct dilatation greater than 5 mm or proximal pancreatic atrophy. For patients with a pancreatic mass, if their radiological images show homogeneous enhancement on the portal venous phase, the absence of significant upstream main pancreatic duct dilatation greater than 5 mm, and the absence of proximal pancreatic atrophy, then conducting further evaluations should be considered to avoid performing unnecessary surgery.