IgG4-related systemic disease mimicking renal pelvic cancer: a rare case

IgG4-Related Disease Mimicking Unilateral Urothelial Carcinoma: A Rare Case Report and Literature Review

Immunoglobulin G4-related disease (IgG4-RD) is an autoimmune-mediated disorder with heterogeneous multiorgan manifestations. Early identification and treatment of IgG4-RD are crucial for organ function recovery. Rarely, IgG4-RD manifests as a unilateral renal pelvic soft tissue mass that may be misdiagnosed as urothelial malignancy, resulting in invasive surgical intervention and organ damage. Here we present a 73-year-old man who had a right ureteropelvic mass with hydronephrosis detected by enhanced computed tomography. Right upper tract urothelial carcinoma and lymph node metastasis was highly suggested based on the image findings. However, IgG4-RD was suspected due to his past history of bilateral submandibular lymphadenopathy, nasolacrimal duct obstruction, as well as a high serum IgG4 level of 861 mg/dL. The ureteroscopy with tissue biopsy showed no evidence of urothelial malignancy. His lesions and symptoms improved after glucocorticoid treatment. Hence, a diagnosis of IgG4-RD was made, with the phenotype of classic Mikulicz syndrome with systemic involvement. The manifestation of IgG4-RD as a unilateral renal pelvic mass is rare and should be kept in mind. A ureteroscopic biopsy and serum IgG4 level measurement can help in the diagnosis of IgG4-RD in patients with a unilateral renal pelvic lesion.

A case of IgG4-related interstitial nephritis with ureteral obstruction: case report and literature review

BACKGROUND

IgG4-related disease (IgG4-RD) is a newly discovered systemic disease that can affect any organ or tissue in the body. IgG4-related kidney disease (IgG4-RKD) is relatively rare but essential to IgG4-RD. However, there are few reports of IgG4-RD mimicking malignant ureteral tumors leading to hydronephrosis. We report here a rare case of IgG4-RD involving the ureter.

CASE PRESENTATION

An 87-year-old man presented to our nephrology department with anorexia, nausea, and acute kidney injury in November 2020. Urinary computed tomography (CT) examination revealed a right lower ureter mass with right renal and ureter hydronephrosis. The serum level of IgG4 was 1890 mg/dL, and the concurrently renal biopsy revealed extensive infiltration of IgG4-positive plasma cells in renal interstitium, which was diagnosed as IgG4-associated tubule-interstitial nephritis(IgG4-TIN). The renal function improved significantly after double-J tube implantation of the right ureter and moderate-dose hormone therapy. The serum IgG4 decreased to the normal range, and the right lower ureter mass almost disappeared after one year of low-dose hormone maintenance therapy.

CONCLUSION

IgG4-RD can present as a mass in the renal pelvis and (or) ureter, leading to hydronephrosis. Therefore, early recognition of this disease is significant. Most patients respond well to hormonal therapy to avoid surgical treatment due to misdiagnosis as malignant tumors, causing secondary harm to patients.

Immunoglobulin G4-related kidney disease involving the renal pelvis and perirenal fat: A case report

BACKGROUND

Immunoglobulin (Ig) G4-related disease (IgG4-RD) is an autoimmune disease associated with chronic and progressive inflammation and fibrosis. It is difficult to differentiate IgG4-RD involving the kidney from infectious diseases and malignancy on imaging.

CASE SUMMARY

We report the case of a 51-year-old Chinese man whose abdominal computed tomography scan showed diffuse bilateral enlargement of the kidneys and perirenal fat, thickening of the renal pelvic walls, and hydronephrosis of the right kidney. Relevant laboratory test results showed a serum creatinine level of 464 μmol/L. The patient was diagnosed with acute renal failure and was started on intermittent hemodialysis. Further tests revealed high serum IgG4 levels (20.8 g/L) and an enlarged right submaxillary lymph node. Biopsy and histopathological examination of the enlarged node led to the diagnosis of IgG4-RD. After corticosteroid therapy, his serum creatinine level quickly decreased to near normal levels.

CONCLUSION

IgG4-RD affecting the renal pelvis or perirenal fat is rare, with atypical imaging features. Multidisciplinary consultation is critical for accurate diagnosis and treatment of this disease. Suspected cases should undergo biopsy to avoid misdiagnosis.

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.

IgG4-related disease mimicking renal pelvis tumor with peritoneal carcinomatosis

IgG4-RD may rarely present as a retroperitoneal fibrosis, mimicking carcinomatosis. Clinicians should consider this disease when encountering an idiopathic peritoneal and retroperitoneal fibrosis with renal involvement and hydronephrosis.

CT Findings of Upper Urinary Tract Lesions in IgG4-Related Disease: Comparison With Urothelial Carcinoma

OBJECTIVE. IgG4-related disease is characterized by extensive infiltration of IgG4-positive plasma cells and fibrosis in various organs. The objective of this study is to investigate CT findings of IgG4-related lesions involving the upper urinary tract and compare them with those of urothelial carcinomas. MATERIALS AND METHODS. This study reviewed pretreatment CT images of 13 consecutive patients with IgG4-related disease with upper urinary tract lesions and 80 consecutive patients with urothelial carcinomas. The findings assessed were laterality, location, growth pattern, margins, internal structure, presence of calcification and lipid component, enhancement pattern, and extraurinary findings. RESULTS. Bilaterality (p < 0.0001), an extramural growth pattern (p < 0.0001), a greater number of affected segments (p = 0.04), and a gradual dynamic enhancement pattern (p < 0.001) were significantly more frequent in patients with IgG4-related disease. With regard to extraurinary findings, paraaortic fat stranding (p = 0.03), presacral fat stranding (p < 0.001), fat stranding of the pelvic walls (p < 0.001), and aortic involvement (p < 0.001) were seen more frequently in patients with IgG4-related disease; on the other hand, there was no statistically significant difference in terms of frequency of pancreatic involvement. Hydronephrosis and renal involvement were seen more frequently in patients with urothelial carcinoma, although the difference was not statistically significant. CONCLUSION. CT findings suggestive of IgG4-related upper urinary tract lesions in comparison with urothelial carcinoma are bilateral and have a longer urinary tract involvement and exhibit an extramural growth pattern, ill-defined margins, a gradual enhancement pattern, aortic involvement, and fat stranding in the paraaortic, presacral, or pelvic wall areas.

Renal Pelvis Involvement of Immunoglobulin G4-Related Disease Mimicking Malignancy on 18F-FDG PET/CT

A 70-year-old woman with bilateral submandibular gland enlargement was referred to our hospital. Submandibular gland biopsy indicated immunoglobulin G4 (IgG4)-related disease (IgG4-RD) involvement. Contrast-enhanced CT was undergone for evaluation of IgG4-RD and revealed a mass located at the left renal pelvis. F-FDG PET/CT showed bilateral FDG-avid submandibular gland and a hypermetabolic mass in the left renal pelvis. The lesions were decreased in both size and metabolism on follow-up PET/CT 2 months after treatment with prednisone. This case illustrated a rare site for IgG4-RD, and the renal pelvis involvement should be considered into differential diagnosis in patients with IgG4-RD history.

Recent advances in understanding and managing IgG4-related disease

IgG4-related disease was only recently discovered, so its description, management, and new discoveries related to its etiology are rapidly evolving. Because IgG4 itself is a unique antibody which is intimately related to the diagnosis of the disease, the role of plasmablasts in the pathophysiology remains an active area of discussion. Recent studies have uncovered a possible role for CD4-positive cytotoxic T lymphocytes, T follicular helper cells, and M2 macrophages. The clinical presentation is variable and can be vague, as this disease affects many organs and new presentations are continuing to be described. The diagnosis depends on clinical and histopathological assessment. The mainstay of treatment is with glucocorticoids, but rituximab has recently shown promise. Monitoring disease activity using imaging modalities (including positron emission tomography) and serum markers is imperative, as relapses are common. IgG4-related disease spans many medical disciplines but is a treatable condition with which all clinicians should be familiar.

IgG4-related inflammatory pseudotumor of the renal pelvis involving renal parenchyma, mimicking malignancy

Background

IgG4-related disease is a recently recognized systemic disease characterized by storiform fibrosis with infiltration of IgG4-positive plasma cells. In rare incidences, IgG4-related renal disease can present as a solitary mass lesion at renal pelvis and can pose a diagnostic challenge since these lesions mimic malignancy. Herein, we present a rare case of IgG4-related disease presenting as inflammatory pseudotumor lesion, involving the renal pelvis and also neighboring renal parenchyma.

Case presentation

A 75-year-old man with no history of IgG4-related disease underwent computed tomography (CT) scan for evaluation of prostatic cancer. The CT scan incidentally revealed a mass lesion located at the right renal pelvis. Radiologic findings were highly suggestive of malignancy. Therefore, the patient underwent right nephroureterectomy. Microscopically, the mass lesion showed storiform fibrosis with diffuse and intense inflammatory cell infiltration. Infiltrating cells were mainly histiocytes and plasma cells. Tubulointerstitium adjacent to the lesion also showed fibrosis with abundant plasmacytic infiltration. Immunohistochemical staining revealed the presence of IgG4-positive plasma cells in both the mass lesion and tubulointerstitium (mean of 94/HPF per field).

Conclusion

Considering these findings, we diagnosed the mass lesion as IgG4-related inflammatory pseudotumor of the renal pelvis. In patients with renal pelvic masses, IgG4-related inflammatory pesudotumor should be considered in the differential diagnosis to avoid unnecessary surgical intervention.

IgG4-related kidney disease from the renal pelvis that mimicked urothelial carcinoma: a case report

Background

IgG4-related kidney disease is a comprehensive term for renal lesions associated with IgG4-related disease, which mainly manifests as plasma cell-rich tubulointerstitial nephritis with increased IgG4+ plasma cells and fibrosis. IgG4-related kidney disease in the renal pelvis is rare.

Case presentation

We describe a 53-year-old Asian woman who was referred to our hospital with a space-occupying renal lesion discovered by medical examination. A physical examination and laboratory evaluation revealed no significant abnormalities. Computed tomography scans showed a soft-tissue mass with an irregular border and mild homogeneous enhancement in the right renal pelvis and calyces. A positron emission tomography/computed tomography scan revealed soft-tissue density shadows with increased radionuclide uptake. To investigate a suspected pelvic carcinoma, a right ureteronephrectomy was performed. A pathologic examination of the renal sections showed a dense lymphoplasmacytic infiltrate rich in IgG4+ plasma cells, with fibrosis beneath the urothelial epithelium of the renal pelvis. Postoperatively, the serum IgG4 level was significantly elevated. The patient was diagnosed with IgG4-related kidney disease.

Conclusion

We present a case of IgG4-related kidney disease mimicking urothelial carcinoma in the renal pelvis. When a buried and solitary hypovascular tumor is detected in the kidney, we must consider IgG4-related kidney disease as a differential diagnosis. Accordingly, elevated serum IgG4, radiologic findings, and pathologic examination may improve the diagnosis.