IgG4-Related Kidney Disease: Report of a Case Presenting as a Renal Mass

Renal Manifestations of IgG4-Related Disease: A Concise Review

IgG4-related disease (IgG4-RD) is an immune-mediated disorder marked by fibro-inflammatory masses that can infiltrate multiple organ systems. Due to its relatively recent discovery and limited understanding of its pathophysiology, IgG4-related disease may be difficult to recognize and is consequently potentially underdiagnosed. Renal involvement is becoming regarded as one of the key features of this disease. To date, the most well-recognized renal complication of IgG4-related disease is tubulointerstitial nephritis, but membranous glomerulonephritis, renal masses, and retroperitoneal fibrosis have also been reported. This concise review has two objectives. First, it will briefly encapsulate the history, epidemiology, and presentation of IgG4-related disease. Second, it will examine the reported renal manifestations of IgG4-related disease, exploring the relevant histology, imaging, clinical features, and treatment considerations. This synthesis will be highly relevant for nephrologists, rheumatologists, general internists, and renal pathologists to raise awareness and help improve early recognition of IgG4-related kidney disease (IgG4-RKD).

Unique case of IgG4-related disease of the renal pelvis involving the inferior vena cava masquerading as locally advanced urothelial cancer

Immunoglobulin G4-related disease (IgG4-RD) is a systemic disease which can affect any organ or tissue in the body but most commonly affects the pancreas, biliary ducts, salivary glands, ocular system and lymph nodes; renal involvement is relatively uncommon and there are no previous reported cases of inferior vena cava involvement. Herein, a 48-year-old Asian man with an unremarkable medical history was found to have an obstructing right renal pelvis mass extending to and involving the inferior vena cava, highly suspicious for upper tract urothelial carcinoma that could not be ruled out based on ureteroscopy and urine cytology. Open radical nephroureterectomy with enbloc resection of a segment of the inferior vena cava and left renal vein ostium was performed, with reconstruction of the inferior vena cava and left renal vein with polytetrafluoroethylene grafts. Final histopathology confirmed the diagnosis of IgG4-related disease. This case demonstrates that IgG4-related disease can mimic upper tract urothelial cancer and should be considered as a diagnosis in atypical presentations of tumours of the upper urinary tract.

Immunoglobulin G4-related renal disease masquerading as renal pelvic tumor

The recently recognized immunoglobulin G4 (IgG4)-related disease presenting as renal pelvic pseudotumor is rare. A definitive diagnosis is often difficult to obtain preoperatively, with patients being subjected to radical surgery due to suspicion of malignancy. We present a 64-year-old male with lower urinary tract symptoms, who, on evaluation had a right renal pelvic tumor on imaging and ureteroscopy. The patient underwent laparoscopic radical nephroureterectomy on clinical suspicion of upper tract urothelial carcinoma. The final histopathology revealed IgG4-related disease.

Successful treatment of tubulointerstitial nephritis in immunoglobulin G4-related disease with rituximab: A case report

BACKGROUND

Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated condition that consisted of disorders that share particular clinical, serologic and pathologic properties. The common presentation of disease includes tumor-like swelling of involved organs and the histopathological findings are a lymphoplasmacytic infiltrate enriched with IgG4-positive plasma cells, and a variable degree of fibrosis that has a characteristic "storiform" pattern in biopsy specimens of tumor-like masses. Major presentations of this disease, which often affects more than one organ, include autoimmune pancreatitis, salivary gland disease (sialadenitis), orbital disease and retroperitoneal fibrosis. The steroid treatment is essential for the treatment of the disease however, other immunosuppressive drugs including cyclophosphamide or rituximab could be an option in resistant cases.

CASE SUMMARY

Herein, we reported a 34-year-old woman whom previously had diagnosed with asthma, rheumatoid arthritis and Sjögren’s syndrome (SS) referred our nephrology department due to acute kidney failure development at the last rheumatology visit. After kidney biopsy she has been diagnosed with IgG4-RD and tubuluointerstitial nephritis. She had been accepted resistant to steroid, mycophenolate mofetil, methotrexate and azathioprine therapies due to receiving in last two years. She refused to receive cyclophosphamide due to potential gonadotoxicity of the drug. Thus, rituximab therapy was considered. She received 1000 mg infusion, 15 d apart and 6 mo later it has been administered same protocol. After one year from the last rituximab dose serum creatinine decreased from 4.4 mg/dL to 1.6 mg/dL, erythrocyte sedimentation rate decreased from 109 mm/h to 13 mm/h [reference range (RR) 0-20], and C-reactive protein decreased from 55.6 mg/L to 5 mg/L (RR 0–6). All pathologic lymph nodes and masses were also disappeared.

CONCLUSION

Patients with IgG4-RD usually misdiagnosed with rheumatologic diseases including systemic lupus erythematous or SS and also they were screened for the presence of malignancy. Rituximab could be an important treatment option in cases with steroid resistant tubulointerstitial nephritis in IgG4-RD.

A case of IgG4-related kidney disease with predominantly unilateral renal atrophy

A 73-year-old Japanese woman was diagnosed with type 1 autoimmune pancreatitis (AIP) without kidney lesions. She was treated with prednisolone (PSL) 30 mg/day, and her AIP symptoms promptly improved, after which the PSL dose was gradually tapered to 5 mg/day. Her renal function had remained normal (serum creatinine 0.7 mg/dL) until 1 year before the current admission without any imaging abnormalities in the kidney. However, during this past year her renal function gradually declined (serum creatinine 1.1 mg/dL). Follow-up computed tomography incidentally revealed unilateral renal atrophy, which rapidly progressed during the subsequent 10-month period without left kidney atrophy. A diagnosis of IgG4-RKD probably due to TIN was made, and we increased the dose of prednisolone to 30 mg/day. 1 month after administration, multiple low-density lesions on both kidneys were improved slightly but almost all lesions persisted as atrophic scars. Our case suggested that unilateral renal atrophy can develop in patients with IgG4-related tubulointerstitial nephritis without hydronephrosis caused by retroperitoneal fibrosis, and that monitoring the serum creatinine levels is not always sufficient, thereby highlighting the importance of regular imaging monitoring to detect newly developing kidney lesions.

Perirenal capsule and scrotal involvement in immunoglobulin G4-related kidney disease: case-based review

Immunoglobulin G4-related disease (IgG4-RD) is a chronic, immune-mediated-, systemic disease that is characterized by IgG4 plasma cell infiltration with fibrotic changes in various organs. The most affected organs are pancreas and salivary glands. Kidney can be rarely involved, and is usually represented as a renal mass and organomegaly. Usually, elevated levels of serum IgG4 more than 135 mg/dl with organ-specific features and biopsy results showing enriched infiltration of IgG4-positive plasma cells are needed to diagnose the disease. However, we experienced two unusual cases of IgG4-RD involving kidney. IgG4-related kidney disease (IgG4-RKD) was first reported as an extra pancreatic feature of autoimmune pancreatitis(AIP) in 2004. Herein, we describe two cases of such unique presentation of IgG4RKD and a literature review focusing on clinicopathologic features of IgG4RKD. Our cases are distinct in the fact that IgG4RD invades unusual organs such as perinephric capsule or scrotum. We reported the patient who showed extinct perirenal capsule invasion with multi-organ involvement including exocrine glands in comparison to previous IgG4RKD that often involved in renal parenchyma and renal pelvis lesions. And the other patient had scrotal invasion with multifocal renal parenchymes. Referring to the features observed in these two cases, we could propose that as every organ can be related to IgG4RD, we propose clinicians to confirm the disease using imaging, serologic, and pathologic studies. We also reviewed previous reports of IgG4-RKD and summarized diverse imaging findings and pathologic features.