Importance of Awareness and Careful Follow-Up of Suspected IgG4-Related Periaortitis.

IgG4-related disease may cause large vessel vasculitis, which often affects males in their 60s. Here, we report a case of suspected IgG4-related periaortitis in a 76-year-old man with lower left-side chest pain and hypertension based on computed tomography findings of thickened lesions surrounding the abdominal aorta and mesenteric arteries after ruling out acute cardiovascular diseases. His serum IgG4 levels were high, but the C-reactive protein and D-dimer levels were within normal limits. Because IgG4-related periaortitis was suspected, the patient was carefully monitored for blood pressure control, inflammatory markers, and renal function. Steroid therapy was not initiated, however, due to the difficulties performing a biopsy targeting periaortitis to obtain a definitive diagnosis and possible severe complications. During follow-up observation, IgG4-related kidney disease was suspected based on a slight increase in the serum creatinine levels and a renal biopsy was considered. Just before performing the renal biopsy, we observed left renal hydronephrosis caused by spreading retroperitoneal fibrosis. Immediate ureteral stent implantation and initiation of steroid therapy successfully improved the renal function and decreased the serum IgG4 level, respectively. Although relatively rare, IgG4-related periaortitis/periarteritis and retroperitoneal fibrosis should be considered in the differential diagnosis of aortic diseases, even after ruling out serious major acute cardiovascular diseases. Cardiologists should also be aware of the possible progression and systemic spread of this disease.