IgG4-related sclerosing disease is a novel clinicopathological entity characterized by fibrosis, extensive infiltration of IgG4-positive plasma cells, and serum IgG4 elevation. This disorder includes a variety of diseases, such as autoimmune pancreatitis, retroperitoneal fibrosis, sialadenitis, thyroiditis, inflammatory abdominal aneurysm, tubulointerstitial nephritis, and inflammatory pseudotumor [World J Gastroenterol 2008;14:3948-3955]. A 71-year-old man visited our hospital with the complaint of left flank pain and gross hematuria. Computed tomography (CT) revealed left hydronephrosis and a thick retroperitoneal soft tissue mass around the ureteropelvic junction, suspicious of renal pelvic cancer. Urine cytology using a urine sample from the left renal pelvis was negative. On laboratory examination, serum levels of IgG and IgG4 were found to be elevated. The patient refused tumor biopsy. Therefore, he was treated with corticosteroid therapy on the basis of a clinical diagnosis with IgG4-related retroperitoneal fibrosis. Regression of the retroperitoneal mass as well as improvement of left hydronephrosis and decrease in serum IgG4 levels were accomplished. These effects strongly suggested that the present case was an IgG4-related retroperitoneal fibrosis. However, in this instance, since we could not completely rule out malignancies by biopsy, careful follow-up was necessary with these points in mind.

1.
Neild GH, Rodriquez-Justo M, Wall C, Connolly JO: Hyper-IgG4 disease: report and characterization of a new disease. BMC Med 2006;4:23.
2.
Uibu T, Oksa P, Auvinen A, et al: Asbestos exposure as a risk factor for retroperitoneal fibrosis. Lancet 2004;363:1422-1426.
3.
Vaglio A, Salvarani C, Buizo C: Retroperitoneal fibrosis. Lancet 2006;367:241-251.
4.
Aalberse RC, Stapel SO, Schuurman J, et al: Immunoglobulin G4: an odd antibody. Clin Exp Allergy 2009;39:469-477.
5.
Miura H, Miyachi Y: IgG4-related retroperitoneal fibrosis and sclerosing cholangitis independent of autoimmune pancreatitis. A recurrent case after a 5-year history of spontaneous remission. JOP 2009;10:432-437.
6.
Kikuno N, Sato H, Ryoji O: Case of IgG4-related retroperitoneal fibrosis with concomitant rheumatoid arthritis. Int J Urol 2010;17:1011-1012.
7.
Cavalleri A, Brunner P, Monticelli I, et al: CT-guided biopsy in two cases of retroperitoneal fibrosis. Clin Imaging 2008;32:230-232.
8.
Takato H, Yasui M, Ichikawa Y, et al: Nonspecific interstitial pneumonia with abundant IgG4-positive cells infiltration, which was thought as pulmonary involvement of IgG4-related autoimmune disease. Intern Med 2008;47:291-294.
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