Đặc điểm hình ảnh bệnh viêm tụy tự miễn liên quan IgG4 tại Bệnh viện Bạch Mai

Abstract

Objective: To describe the imaging characteristics of IgG4-related autoimmune pancreatitis on computed tomography (CT) and/or magnetic resonance imaging (MRI).

Subjects and

Methods: This study describes a series of 27 cases diagnosed with IgG4-related autoimmune pancreatitis according to the 2018 clinical diagnostic criteria of the Japan Pancreas Society (JPS 2018 criteria) at Bach Mai Hospital from February 2020 to August 2025, recording the imaging characteristics 27 patients (21 males and 6 females), with a mean age of 64.2 years (range: 24–85), was studied. Diffuse pancreatic involvement was observed in 19/27 patients (70.4%), focal involvement in 3/27 (11.1%), segmental involvement in 2/27 (7.4%), and multifocal involvement in 3/27 (11.1%). Among non-diffuse types, lesions were located in the pancreatic head in 100% of cases (8/8), in the body in 50% (4/8), and in the tail in 37.5% (3/8). The capsule-like rim sign was observed in 22/27 patients (81.5%). Regarding enhancement characteristics: during the arterial phase, 13/27 patients (48.1%) showed speckled/dotted enhancement, and 5/27 patients (18.5%) showed hypoenhancement, while all lesions (100%) demonstrated homogeneous delayed enhancement. MRI was performed in 23/27 patients. Pancreatic ductal narrowing was detected in 21/23 patients (91.3%). The duct-penetrating sign was identified in 4/8 non-diffuse cases (50%). An enhanced duct sign was present in 13/23 patients (56.5%). All patients showed restricted diffusion on DWI/ADC, with variable signal intensities on T1W and T2W sequences. Extraparenchymal involvement was present in 23/27 patients (85.2%), most commonly affecting the biliary tract (22/27, 81.5%), followed by the kidneys (7/27, 25.9%), bilateral submandibular glands (1/27, 3.7%), and retroperitoneal fibrosis (1/27, 3.7%). Misdiagnosis as malignant disease occurred in 6/27 patients (22.2%), including both pancreatic and biliary tract lesions.

Conclusion: IgG4-related AIP demonstrates characteristic imaging features, including specific patterns of parenchymal involvement, enhancement behavior, MPD abnormalities, capsule-like rim, and associated extrapancreatic IgG4-related lesions. Recognition of these imaging findings is essential for accurate diagnosis and to avoid unnecessary surgical interventions due to misdiagnosis as malignant disease.