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Paper text:
immunoglobulin ( ig ) g4-related sclerosing disease is an immunoglobulin deposition disease characterized by infiltration of organs by igg4-positive plasma cells .
manifestations include retroperitoneal fibrosis , dacryoadenitis , sialadenitis , thyroiditis , pneumonitis , pancreatitis , sclerosing cholangitis , tubulointestinal nephritis , prostatitis , and hypophysitis .
regardless of organ involvement , biopsy with review of histopathology and immunohistochemical staining for igg4 are essential for diagnosis .
herein we describe a case of igg4-related sclerosing disease that involved the left pelvocaliceal system and extended to the level of the left ureter , thereby causing left hydronephrosis .
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 .
his laboratory data showed a white blood cell count of 4.410/mm , 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 .
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 ( fig .
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 ( fig .
there were adhesions between the hard mass lesions and the left ureter around the ureteropelvic junction .
the histological examination was negative for malignancy but showed soft tissue mixed lymphocytic infiltration with germinal centers ( fig .
igg4 immunostaining revealed numerous cells positive for igg and more than 50 igg4-positive cells per high - powered field ( fig .
the patient 's serum igg level was increased to 1,839 mg / dl ( normal range , 870 to 1,700 mg / dl ) .
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 .
lately , igg4-related sclerosing disease has been proposed to describe the group of autoimmune disorders involving connective tissue . prominent infiltration of igg4-positive plasma cells in affected tissues is a characteristic feature of this disease .
an increasing number of sclerosing diseases are recognized as part of the disease spectrum , such as autoimmune pancreatitis , sclerosing cholangitis , chronic cholecystitis , chronic sclerosing sialadenitis , retroperitoneal fibrosis , tubulointestinal nephritis , interstitial pneumonia , and lymphocystic hypophysitis . in our case , fibrotic tissues around the left kidney and ureter resulted in hydronephrosis .
a chest ct scan showed the left paraesophageal , right hilar , and both interlobar lymph nodes to be enlarged and the presence of a small nodule in the left lower lobe .
the abdominal ct showed an infiltrating soft tissue mass involving the left pelvocaliceal system and extending to the left midureter .
immunohistochemical staining of the specimen showed more than 50 igg4-positive cells per high - powered field .
histopathology and immunohistochemical staining for igg4 are the most valuable diagnostic tools in igg4-related systemic disease .
thus , further randomized trials are needed . in our case , although hydronephrosis was present , the patient had no signs of renal functional impairment .
if severe hydronephrosis and renal functional impairment are present , ureteral stent indwelling is needed . in periureteral igg4-related systemic sclerosing disease ,
biopsy should be regarded as a diagnostic option for diseases such as retroperitoneal fibrosis , retroperitoneal sarcoma , lymphoma , and retroperitoneal hematoma , which are difficult to differentiate with ct scans . also , the relationship between igg , igg4 , and perirenal masses must to be kept in mind .
urologists should be aware of the possibility of igg4-related disease in the differential diagnosis of a periureteral mass .
immunoglobulin ( ig ) g4-related sclerosing disease is a newly defined clinicopathological entity characterized by lymphoplasmacytic infiltration of igg4-positive plasma cells and varying degrees of fibrosis within affected tissues . 
 patients usually exhibit multisystem involvement and often respond well to steroid and immunosuppressive therapy . 
 this report presents a case of igg4-related sclerosing disease involving the ureter and kidney . 
 we hope to bring igg4-related sclerosing disease to the attention of urologists , because it is an uncommon disease that commonly responds to systemic corticosteroids .