RESUMO
Objective To explore the clinical manifestation,diagnosis and treatment of IgG4-related retroperitoneal fibrosis (IgG4-RRPF) and IgG4-related disease (IgG4-RD).Methods The clinical data of a case of IgG4-RRPF was analyzed retrospectively,the related literatures were reviewed,and a novel clinical entity IgG4-RD was introduced.Results The patient was a 52-year-old man with the complaint of left lower abdominal pain due to left hydronephrosis.CT and MRI revealed a soft tissue mass at the left psoas major muscle.PET-CT showed increased FDG uptake.After biopsy,the pathological diagnosis was consistent with IgG4-RD.The patient was diagnosed as IgG4-RRPF and treated with prednisone.The symptoms improved and retroperitonea] mass reduced.According to review the latest literatures,it is found that IgG4-RRPF was socalled idiopathic retroperitoneal fibrosis (IRF) formerly.Conclusion IgG4-RRPF is a rare disease in IgG4-RD spectrum,characterised by the presence of a retroperitoneal tissue,consisting of chronic inflammation and marked fibrosis,which often entraps the ureters or other abdominal organs.Hematological examination shows elevated serum IgG4 concentration (≥ 1.35 g/L).Histopathological examination shows marked tissue infiltration by lymphocytes and IgG4-plasma cells with fibrosis.Glucocorticoids are the first line of therapy.