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

Abstract

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.

IgG4-Related Disease With Testicular Involvement: A Case Report and Review of Literature

“…Thus, the importance of long-term monitoring of patient's serum IgG4, IgE, and peripheral eosinophils is highlighted. In clinical practice, in addition to careful physical examination, when a patient has a previous diagnosis of IgG4-RD or has a localized organ enlargement suggestive of IgG4-RD morphology, complaining of testicular pain, swelling, and mass, testing the serum IgG4 level is essential as it plays a vital role in the diagnosis and monitoring of IgG4-RD recurrence (6). When serum IgG4 is normal, the surgeon's evaluation is a priority and important.…”

IgG4-related kidney disease and retroperitoneal fibrosis: An update

“…Since the border between affected and unaffected areas is very unclear with bilateral enlarged kidneys, diffuse patchy involvement is a more suitable name in such cases (Figure 1(B)) [15,35]. Extrarenal lesions and those located on the renal capsule are another salient feature of this disease, and are called 'rim-like lesion of the kidney' (Figure 1(C)) [36][37][38][39][40]. This radiological finding corresponds to the capsule-like low-density rim of Type 1 autoimmune pancreatitis (AIP).…”

Rapidly Progressive Kidney Failure Associated with Perirenal Capsular Lesion Due to IgG4-Related Disease

“…Perirenal soft tissue infiltration associated with IgG4-RD is rare ( 2 ). Cho et al and Chen et al reported perirenal capsule infiltration due to IgG4-RD ( 3 , 4 ). Kidney failure was mild and not rapidly progressive in these cases, and the detailed mechanism underlying the development of kidney failure was not explained.…”

“…Hydronephrosis associated with retroperitoneal fibrosis is another common abnormality. Perirenal lesions are a rare presentation of IgG4-RD and few studies have reported on their clinical significance in detail ( 3 , 4 ).…”