Renal-Limited IgG4-Related Disease Presenting as Hypodense Lesions Found During Surveillance Imaging in a Patient With High-Grade Urothelial Cell Carcinoma.

Renal lesions as the initial presentation of IgG4-related disease (IgG4-RD) and isolated IgG4-related kidney disease (IgG4-RKD) are rare. 1,2 A 65-year-old male with a history of high-grade urothelial cell carcinoma in remission was found to have multiple renal lesions on surveillance imaging (Figure 1A).