Background IgG4-related disease (IgG4-RD) is not rare and clinically important disease. It is very difficult to confirm the diagnosis because IgG4 positive lymphocyte infiltrates various organs such as pancreas, salivary glands, retroperitoneum, and kidney. Especially, lymphadenopathy is a common symptom in IgG4-RD patients. In addition, some cases have only lymphadenopathy in IgG4-RD. On the other hand, we presented that FDG-PET/CT was useful to improve a diagnosis rate in our facility. However, it is difficult for the rheumatologist to distinguish lymphadenopathy from other benign disorders such as viral infection and sarcoidosis using FDG-PET/CT only.
Objectives We examine the tool to distinguish for the case of lymphadenopathy suspected IgG4-RD.
Methods We enrolled 26 cases with suspected IgG4-RD in our facility between Jan. 2008 and Dec. 2014. Furthermore, we classified these 26 cases into IgG4-RD (IgG4- RD group) and other benign disorders (non IgG4-RD group). The diagnosis for IgG4-RD was based on comprehensive diagnostic criteria for IgG4-RD. We investigated the serum IgG4 levels, sIL2-R levels and maximum standardized uptake value (SUVmax) of abnormal lymph node accumulation by FDG-PET/CT. We retrospectively examined the relations of these three values.
Results Lymphadenopathy were detected in 19 of 26 cases (IgG4-RD definite: 8, IgG4-RD possible: 5, IgG4-RD probable: 1, infectious disease: 2, SLE: 1, EGPA: 1, Castleman disease: 1). In IgG4-RD group, serum IgG4 level elevated and serum sIL-2R levels decreased in comparison with non IgG4-RD group respectively. There is no difference between two groups in SUVmax.
Conclusions In our study, we examined the differentiation of lymphadenopathy. We proved that it was difficult to distinguish IgG4-RD from other benign disorders for lymphadenopathy only by FDG-PET/CT. We suggested that combination of serum IgG4 and sIL-2R levels is useful for diagnosis of IgG4-RD with lymphadenopathy.
Umehara H, Okazaki K, Masaki Y, et al. Comprehensive diagnostic criteria for IgG4-related disease (IgG4-RD), 2011. Mod Rheumatol. 2012 Feb;22(1):21-30.
Nakatani K. Utility of FDG PET/CT in IgG4-related systemic disease Clin Radiol. 2012 Apr;67(4):297-305.
Disclosure of Interest None declared
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