IgG4 related disease of the ureter (inflammatory pseudotumor)

MRI diagnosis of tumor‑like IgG4 masses in bilateral distal ureters: A case report

IgG4 masses in the bilateral distal ureters are rare and frequently misdiagnosed. The present study reported the case of a 55-year-old male patient with IgG4-related disease (IgG4-RD) who had symmetrical soft tissue masses of the bilateral distal ureters found on magnetic resonance imaging (MRI) with a significant increase in the serum levels of IL-6, IgG4 and IgE. Regarding treatment, this patient received prednisone acetate tablets (40 mg/day) and mycophenolate mofetil dispersible tablets (1 g/day). During the follow-up, significant reductions in the levels of IgG4 and IgE were found after 30 days. MRI after 6 months indicated complete disappearance of the masses. The prognosis has been good so far. In clinical practice, it is necessary to consider the possibility of IgG4-RD in cases with soft tissue masses surrounding both ureters and elevated levels of serum IgG4.

Immunoglobulin G4-related Disease of the Genitourinary System: Spectrum of Imaging Findings and Clinical-Pathologic Features

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disease characterized by focal or diffuse organ infiltration of IgG4-bearing plasma cells. The diagnosis of IgG4-RD is based on a combination of clinical, serologic, radiologic, and histopathologic findings. IgG4-RD has been reported to affect almost all organ systems. The kidney is the most frequently involved of the genitourinary organs. The most common renal manifestation of IgG4-RD is IgG4-RD tubulointerstitial nephritis, followed by membranous glomerulonephropathy and, less frequently, obstructive nephropathy involving the renal pelvis, ureter, or retroperitoneum. Renal parenchymal lesions may appear as multiple nodular lesions, diffuse patchy infiltrative lesions, or a single nodular lesion. Multiple small nodular cortical lesions are the most common imaging findings of IgG4-RD involving the kidney. Renal pelvic, sinus, or perinephric lesions can also occur. IgG4-RD involvement of other genitourinary organs including the ureter, bladder, urethra, and male and female reproductive organs is rare compared with kidney involvement but may show variable imaging findings such as a localized mass within or surrounding the involved organ or diffuse enlargement of the involved organ. Imaging findings of IgG4-RD involving the genitourinary system are nonspecific but should be differentiated from inflammatory and neoplastic lesions that mimic IgG4-RD. The online slide presentation from the RSNA Annual Meeting is available for this article. ^©RSNA, 2020.

IgG4-related inflammatory pseudotumor: A systematic review of histopathological features of reported cases

OBJECTIVES

There is marked inconsistency in reporting the key features of IgG4-related inflammatory pseudotumor (IPT) cases. We aimed to analyze the various aspects of IgG4-related IPTs and to test the performance of the consensus criteria for their diagnosis.

METHODS

PubMed database was searched for IgG4-related IPT cases. The data regarding patient demographics, clinical presentation, laboratory findings, histopathological features, and treatment response are extracted and are presented here in a descriptive manner.

RESULTS

The study included 40 papers describing the clinicopathological features of 83 IPTs in 80 patients. Seventeen cases were diagnosed on biopsies; while remaining were diagnosed on excision specimens. Among these, 50 cases were categorized as highly suggestive and 24 cases as probable for IgG4RD; while nine cases had insufficient histopathological evidence of IgG4RD. Two cases diagnosed on biopsies having insufficient evidence of IgG4RD showed partial or no response to steroids; while 12/14 cases (85.71%) diagnosed on biopsies that were histologically suggestive or probable for IgG4RD showed prompt response to steroids.

CONCLUSION

Many reports have not specifically mentioned the full histopathological findings of IgG4-related IPTs that may hinder in refining the diagnostic criteria of IgG4RD. The IgG4-related IPTs diagnosed on biopsies with requisite features showed prompt response to steroids indicating specificity of histopathological findings in predicting treatment response.

IgG4-related inflammatory pseudotumor of the kidney mimicking renal cell carcinoma: A case report

IgG4-related disease is a recently recognized clinical entity. It is characterized by diffuse organ swelling or mass formation, a dense lymphoplasmacytic infiltrate rich in IgG4-positive plasma cells with fibrosis and typically an increased serum IgG4 concentration, which may affect various organs. An 80-year-old woman with an otherwise unremarkable previous medical history was revealed to have a renal mass that was indicative of renal malignant carcinoma, for which a radical nephrectomy was performed. The mass was diagnosed as an IgG4-related inflammatory pseudotumor, which was histopathologically confirmed. The patient is currently well without evidence of IgG4-related disease at 3 months post-surgery, and did not require any additional therapy.

IgG4-Related Disease in a Urachal Tumor

IgG4-related disease is a newly recognized fibroinflammatory disorder that has the ability to affect nearly every organ system. It is characterized by tumefactive lesions and fibrosis and closely mimics neoplasms. Only one case of IgG4-related bladder mass has been reported in the literature, but there are no reports of IgG4-related disease in a urachal mass. Herein, we report a 26-year-old male who initially presented with symptoms of recurrent UTI. Work-up revealed a 6 cm urachal tumor, a 1.4 cm pulmonary lesion, and mediastinal lymphadenopathy; all metabolically active on PET scan and suspicious for urachal adenocarcinoma. Lung lesion fine needle aspiration and TURBT pathology revealed inflammation but no evidence of malignancy. The patient underwent a partial cystectomy and umbilectomy with pathology demonstrating dense plasmacytic cells, a high rate of immunohistochemistry staining positive for IgG4 plasma cells, a storiform pattern of fibrosis, and an obliterative phlebitis. Furthermore, the patient had an elevated serum IgG4 level of 227 mg/dL (range 2.4–121 mg/dL). IgG4-related disease is a newly recognized fibroinflammatory disorder that can mimic neoplastic processes and a high index of suspicion and accurate tissue pathology is necessary for an accurate diagnosis.