MRI diagnosis of tumor‑like IgG4 masses in bilateral distal ureters: A case report.

IgG4 masses in the bilateral distal ureters are rare and frequently misdiagnosed. The present study reported the case of a 55-year-old male patient with IgG4-related disease (IgG4-RD) who had symmetrical soft tissue masses of the bilateral distal ureters found on magnetic resonance imaging (MRI) with a significant increase in the serum levels of IL-6, IgG4 and IgE. Regarding treatment, this patient received prednisone acetate tablets (40 mg/day) and mycophenolate mofetil dispersible tablets (1 g/day). During the follow-up, significant reductions in the levels of IgG4 and IgE were found after 30 days. MRI after 6 months indicated complete disappearance of the masses. The prognosis has been good so far. In clinical practice, it is necessary to consider the possibility of IgG4-RD in cases with soft tissue masses surrounding both ureters and elevated levels of serum IgG4.