Malignancies in Korean patients with immunoglobulin G4-related disease

Aim: Several studies have implicated increased risk of malignancy in patients with immunoglobulin G4-related disease (IgG4-RD). Hence, we first evaluated the risk and the type of malignancy in Korean IgG4-RD patients. Method: Clinical and laboratory results of patients fulfilling the comprehensive diagnostic criteria for IgG4-RD were retrospectively collected between January 2006 and November 2015. One hundred and eighteen patients were included, and 35 were classified as having definite, 83 as possible/probable IgG4-RD. We compared baseline clinical and laboratory variables between patients with definite and those with possible/probable IgG4-RD and calculated standardized incidence ratios (SIRs) for malignancies. Results: The median age was 60 years old and 91 patients (77.1%) were male. Malignancies were found in 12 of 118 patients (10.1%), and lymphoma (4, 25.0%) was the most frequent malignancy related to IgG4-RD. Definite IgG4-RD patients had higher serum IgG levels and frequent multiple organ involvement. The overall incidence of malignancy was increased in patients with IgG4-RD compared to the general population (SIR 23.08 [95% CI 11.92–40.31]), and the overall risk of SIRs was highest in non-Hodgkin lymphoma (SIR 400.00 [95% CI 109.00–1024.00]). Conclusion: Our data showed that increased risk of malignancy, especially lymphomas, was observed in Korean IgG4-RD patients.