Rare and atypical imaging manifestations of abdominal lesions associated with IgG4-related disease:CT and MRI findings / 中华放射学杂志

ABSTRACT

Objective To investigate rare and atypical imaging manifestations of abdominal lesions associated with IgG4-related disease (IgG4-RD).Methods Forty-one patients with IgG4-RD proved histopathologically or clinically were investigated retrospectively.All the patients underwent precontrast and dynamic enhancement scan of the abdomen.CT was performed in 32 patients and MR imaging in 27 patients (including both of CT and MRI in 18 patients).Whether tissue and organs of the abdomen were involved was observed,especially rare and atypical imaging manifestations including focal pancreatic lesion,pseudocyst and (or) abscess as well as calcification of pancreas,peripheral blood vessels of pancreas involvement and mass-like lesions were existed.Involvement of the organs including liver,gallbladder,spleen,gastrointestinal tract,mesentery and their manifestations were also observed.Results One to four abdominal organs were involved,the numbers of involved organs were as follows:one organ in 13 patients (31.7％),two organs in 12 patients (29.3％),three organs in 13 patients (31.7％),and four organs in 4 patients (7.3％).The most commonly involved organ of the abdomen was the pancreas which was found in 35 patients.Abdominal extrapancreatic lesions were found in 33 patients.Focal involvement of pancreas as a rare manifestation showed in 11 cases (11/35,31.4％).The patterns were focal and multifocal.Rare cases showed pseudocysts (3/35,8.6％) and abscess was found in 1 case.Capsule-like rim was present around the pancreas lesions in 25 cases.Ten cases showed thick and wide rim with unclear boundaries with adjacent blood vessels,and 7 of them showed the peripheral blood vessels surrounded.Bile duct involvement was observed in 26 patients,and gallbladder involvement was observed in only 2 of them.Rare renal involvement patient has mass-like lesion,with hypointensity on T2WI,then showed decreased enhancement and gradually delayed enhancement.One retroperitoneal fibrosis patient also showed mass-like lesion as an atypical and rare manifestation.Three IgG4-related liver inflammatory pseudotumors were found in 2 patients.Lesions showed iso or hypointensity on T2WI,continuously enhancement,with abnormal edge ring.Mesentery involvement was found in 1 patient.Conclusion Several abdominal lesions associated with IgG4-RD have rare and atypical imaging manifestations.There are specific imaging characteristics,which are helpful for most accurate diagnosis of IgG4-RD.