[A CASE OF IgG4-RELATED DISEASE OF THE URETER DIAGNOSED BY TRANSVAGINAL ULTRASOUND-GUIDED BIOPSY].

IgG4-related disease (IgG4-RD) is a chronic inflammatory disorder that systemically causes tissue fibrosis due to infiltration of IgG4-positive plasma cells. Here, we reported a rare case of ureteral IgG4-RD that formed a nodular lesion and diagnosed by trans-vaginal ultrasound-guided needle biopsy.A 72-year-old woman presented with loss of appetite. The patient underwent Computed Tomography (CT), and she was pointed out the thickening of the left side bladder wall. So we performed a transurethral bladder biopsy under lumber anesthesia, but histopathological findings were almost normal. After that, she developed pyelonephritis repeatedly. We performed CT again. A CT revealed a nodular lesion at the end of her left ureter and hydronephrosis. The tumor was gradually getting larger. So we performed placement the ureteral stent for urinary tract obstruction. Left ureteral urine cytology was classIIIa. We performed transvaginal ultrasound needle biopsy for the nodular lesion of the left ureter. Histopathological findings showed infiltration of lymphocytes and fibrosis and infiltration of IgG4 positive plasma cells: the ratio of IgG4/IgG positive cells>0.6, 30>IgG4 positive plasma cells/high power field. The serum IgG and IgG4 levels were also elevated 1,943 and 210 mg/dl. We finally diagnosed IgG4-RD of the ureter and started using steroid for her treatment. One month later, the tumor had reduced after steroid treatment. The ureteral stent was removed. Since then, recurrent ureteral obstruction of the left ureter has not occurred.IgG4-RD of the ureter with nodular type is rare, and the imaging findings are similar to malignant tumors. Accurate diagnosis is very important to rule out malignancy. In our case, transvaginal needle biopsy was helpful to reach final diagnosis.