A Case of Immunoglobulin G4-Related Disease with Extensive Multiorgan Involvements

IgG4-Related Pseudotumors Mimicking Metastases in Liver and Lungs

A 47-year-old man complained intermittent dull pain at the right upper quadrant abdomen and right neck swelling for 3 months. Blood tests revealed leukocytosis with mild eosinophilia. Computed tomography (CT) showed the presence of multiple nodules in the liver and both lung fields. Positron emission tomography/CT (PET/CT) scans found increased uptake at lymph nodes of the right neck, in the lung, liver, and prostate. The patient was diagnosed with IgG4-related disease (IgG4-RD) based on the biopsy findings from the right neck lymph nodes, showing enriched IgG4-positive lymphoplasmacytic cells. It is often difficult to distinguish IgG4-RD from malignancy, especially in presentations with multiple pseudotumors. This case serves as a reminder that IgG4-RD should be considered in earlier diagnosis, since pseudotumors in multiple organs may imitate tumor metastases.

IgG4-related nephritis and interstitial pulmonary disease complicated by invasive pulmonary fungal infection: a case report

Background

IgG4-related kidney disease (IgG4-RKD) can affect multiple organs, which was first reported as a complication or extra-organ manifestation of autoimmune pancreatitis in 2004. It is characterized by abundant IgG4-positive plasma cells infiltration in tissues involved.

Case presentation

A 69-year-old man presented with cough and renal dysfunction with medical history of hypertension and diabetes. Pathological findings revealed interstitial nephritis and he was initially diagnosed with IgG4-RKD. Prednisone helped the patient to get a remission of cough and an obvious decrease of IgG4 level. However, he developed invasive pulmonary fungal infection while steroid theatment. Anti-fungal therapy was initiated after lung puncture (around cavitary lung lesion). Hemodialysis had been conducted because of renal failure and he got rid of it 2 months later. Methylprednisolone was decreased to 8 mg/day for maintenance therapy. Anti-fungal infection continued for 4 months after discharge home. On the 4th month of follow-up, Chest CT revealed no progression of lung lesions.

Conclusions

The corticosteroids are the first-line therapy of IgG4-RD and a rapid response helps to confirm the diagnosis. This case should inspire clinicians to identify IgG4-related lung disease and secondary pulmonary infection, pay attention to the complications during immunosuppressive therapy for primary disease control.

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.

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.

Immunoglobulin G4-related pleuritis - A case report

Immunoglobulin G4-related disease (IgG4-RD) is a chronic disease that presents with inflammation and fibrosis of involved tissue. It encompasses several disorders previously described using different terms, but all disorders are characterised by IgG4-positive plasma cells and lymphocytes infiltration of tissues. We report a rare case of a 58-year-old man with IgG4-related pleural disease without other systemic manifestations. The diagnosis was based on characteristic changes on PET-CT and typical histopathology in a pleural specimen. The patient’s condition improved following immunosuppressive therapy.