Abstract
PurposeIgG4-related disease (IgG4-RD) is an increasingly recognized clinicopathological disorder with immune-mediated inflammatory lesions mimicking malignancies. A cohort study was prospectively designed to investigate the value of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in characterizing IgG4-RD.MethodsThirty-five patients diagnosed with IgG4-RD according to the consensus criteria were enrolled with informed consent. All patients underwent baseline 18F-FDG PET/CT evaluation. Among them, 29 patients underwent a second 18F-FDG PET/CT scan after 2 to 4 weeks of steroid-based therapy.ResultsAll 35 patients were found with 18F-FDG-avid hypermetabolic lesion(s); 97.1 % (34/35) of these patients showed multi-organ involvement. Among the 35 patients, 71.4 % (25/35) patients were found with more organ involvement on 18F-FDG PET/CT than conventional evaluations including physical examination, ultrasonography, and computed tomography (CT). 18F-FDG PET/CT demonstrated specific image characteristics and pattern of IgG4-RD, including diffusely elevated 18F-FDG uptake in the pancreas and salivary glands, patchy lesions in the retroperitoneal region and vascular wall, and multi-organ involvement that cannot be interpreted as metastasis. Comprehensive understanding of all involvement aided the biopsy-site selection in seven patients and the recanalization of ureteral obstruction in five patients. After 2 to 4 weeks of steroid-based therapy at 40 mg to 50 mg prednisone per day, 72.4 % (21/29) of the patients showed complete remission, whereas the others exhibited > 81.8 % decrease in 18F-FDG uptake.ConclusionF-FDG PET/CT is a useful tool for assessing organ involvement, monitoring therapeutic response, and guiding interventional treatment of IgG4-RD. The image pattern is suggested to be updated into the consensus diagnostic criteria for IgG4-RD.
Highlights
IgG4-related disease (IgG4-RD) has been an increasingly recognized clinical entity in recent years [1,2,3]
As an immune-mediated inflammatory disease characterized by swelling lesions with storiform fibrosis and lymphoplasmacytic infiltration enriched with IgG4-positive plasma cells, IgG4-RD have been found in multiple organs/ tissues, including the pancreas, pancreatobiliary tract, lacrimal gland, salivary gland, lung, retroperitoneal region, and kidney [4]
Our study showed that 18F-FDG positron emission tomography/computed tomography (PET/computed tomography (CT)) could be a useful tool in unsealing the insidious conditions that might lead to severe complications at the early stage
Summary
IgG4-related disease (IgG4-RD) has been an increasingly recognized clinical entity in recent years [1,2,3]. Many medical conditions, such as sclerosing sialadenitis, retroperitoneal fibrosis, and lymphoplasmacytic aortitis, were subsequently reported to be associated with AIP, indicating that these diseases may be part of a spectrum of clinical entities not yet well recognized [9,10,11]. Inadequate understanding may cause misdiagnosis of the disease as malignancies Such misunderstanding can cause high psychological pressure in the patients, excessive examinations, and even unnecessary surgical intervention when the condition can be cured by corticosteroid-based treatment [14, 15]
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