Immunoglobulin G4-Related Systemic Sclerosing Disease: A Case Involving the Ureter and Kidney
A 70-year-old man was transferred to Kyung Hee University Hospital at Gangdong for further evaluation of left hydronephrosis. He had recently visited a private clinic because of dyspepsia, and abdominal ultrasonography had shown left hydronephrosis. The physical examination revealed no tenderness of the abdomen and no costovertebral angle tenderness.\nHis laboratory data showed a white blood cell count of 4.4×103/mm3, hemoglobin of 14.3 g/dL, a platelet count of 164K, a serum creatinine level of 1.1 mg/dL, and an erythrocyte sedimentation rate of 6 mm/h. The results of a liver function test and electrolyte values were within the normal range. Urine analysis showed a white blood cell count of 0-1 and a red blood cell count of 0-1. The results of a urine gram stain were negative. His C-reactive protein concentration was 0.04 mg/dL. An abdominal computed tomographic (CT) scan revealed an enhanced soft tissue mass infiltrating the left renal pelvis of the left kidney and extending to the level of the left mid ureter, causing left hydronephrosis (). A chest CT scan revealed a small, well-defined nodule in the left lower lobe, an enlarged right hilar lymph node, enlarged interlobar lymph nodes, and an enlarged left paraesophageal lymph node ().\nFor pathological confirmation, laparoscopic biopsy of the periureteral lesion was performed by the same method as conventional laparoscopic partial nephrectomy []. There were adhesions between the hard mass lesions and the left ureter around the ureteropelvic junction. Several frozen biopsies of the periureteral mass were performed. No malignant cells were found, but heavy lymphoid cell infiltration was seen. The histological examination was negative for malignancy but showed soft tissue mixed lymphocytic infiltration with germinal centers (). IgG4 immunostaining revealed numerous cells positive for IgG and more than 50 IgG4-positive cells per high-powered field (). The patient's serum IgG level was increased to 1,839 mg/dL (normal range, 870 to 1,700 mg/dL). His serum IgG4 level was 0.420 g/L (normal range, 0.061 to 0.214 g/L). A diagnosis of IgG4-sclerosing disease was made. The patient was initially treated with 40 mg of oral prednisolone daily for 2 weeks with a subsequent decrease in the dosage by 5 mg every 2 weeks. He was maintained on steroid therapy for 3 months, and the follow-up ultrasonography showed minimal hydronephrosis. We plan to keep treating the patient with prednisolone therapy and to perform regular follow-up abdominal CT scans.