Imaging findings of IgG4-related kidney disease without extrarenal organ involvement

Abstract

Rationale: IgG4-related disease (IgG4-RD) is a systemic chronic inflammatory disorder that can affect almost every organ. IgG4-RD includes IgG4-related kidney disease (IgG4-RKD), but lesions affecting the kidney alone or first are very rare, and a complete understanding is lacking. Computed tomography (CT) and magnetic resonance imaging (MRI) findings can show the typical characteristics of IgG4-RKD and provide information for accurate and rapid diagnosis. Patient concerns: We report a case of a 60-year-old woman who was admitted to our hospital for dizziness and instability while walking, her bilateral eyelids were also slightly swollen. She had no medical history. Diagnoses: CT and MRI images of the patient revealed multiple local and diffuse patchy lesions in the bilateral renal parenchyma and mass-like tissue in the bilateral renal pelvis, accompanied by right hydronephrosis. A pathological examination of renal samples showed numerous lymphocyte and plasma cell infiltration. Immunohistochemistry demonstrated approximately 50% of the IgG-positive plasma cells to be IgG4+. The serum IgG level was obviously elevated, with both C3and C4 levels were reduced. The patient was diagnosed with IgG4-RKD. Interventions: The patient received corticosteroid therapy at another hospital. Outcomes: The bilateral kidney lesions were smaller on follow-up CT images. Lessons: IgG4-RKD exhibits some characteristic imaging features. Despite the relatively low incidence of IgG4-RKD, it should be included in differential diagnoses when images show multiple lesions in kidneys with mild and delayed enhancement and hypointensity on T2WI in middle-aged to elderly patients

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

“…Among the cases of IgG4-RD affecting the renal pelvis or perirenal fat reported in the literature, 53.8% (7/13) underwent nephrectomy or nephroureterectomy, and the pathological diagnosis was IgG4-RKD[ 13 - 17 ]. From our literature review, we found that the misdiagnosis rate of IgG4-RD involving the renal pelvis was very high, suggesting that currently, urologists generally lack understanding of this disease[ 18 , 19 ]. This causes a certain delay in the diagnosis and treatment stages.…”

Update on classification, diagnosis, and management of immunoglobulin G4-related disease

“…[42] Contrastenhanced CT is an important tool to evaluate the lesions, which exhibit a variety of imaging features of the bilateral kidneys, such as diffuse patchy involvement, multiple lowdensity lesions, extrarenal lesions located on the renal capsule (so-called rim-like lesion), or renal pelvis thickening with smooth intraluminal surface. [42,43] A solitary mass lesion is rare and very difficult to be distinguished from a malignant tumor. [43] The histopathology of IgG4-TIN presents clearly demarcated margins between affected and unaffected areas, which corresponded to the imaging characteristics of multiple low-density lesions, and lymphoplasmacytic cells infiltrate into and beyond the renal capsule, which is a specific distribution of renal parenchymal lesions, and lesions located outside the renal capsule was thought to correspond to the rim-like lesion in imagings.…”

“…In addition, elevated serum IgG4 levels are commonly observed in IgG4-TIN, and >50% of patients with active disease present with hypocomplementemia [42] . Contrast-enhanced CT is an important tool to evaluate the lesions, which exhibit a variety of imaging features of the bilateral kidneys, such as diffuse patchy involvement, multiple low-density lesions, extrarenal lesions located on the renal capsule (so-called rim-like lesion), or renal pelvis thickening with smooth intraluminal surface [42,43] . A solitary mass lesion is rare and very difficult to be distinguished from a malignant tumor [43] .…”

“…[42,43] A solitary mass lesion is rare and very difficult to be distinguished from a malignant tumor. [43] The histopathology of IgG4-TIN presents clearly demarcated margins between affected and unaffected areas, which corresponded to the imaging characteristics of multiple low-density lesions, and lymphoplasmacytic cells infiltrate into and beyond the renal capsule, which is a specific distribution of renal parenchymal lesions, and lesions located outside the renal capsule was thought to correspond to the rim-like lesion in imagings. [35] In addition, immunoglobulin and complement deposition in the tubular basement membrane (TBM) is another important feature of IgG4-TIN.…”

A Rare Case: IgG4-Related Chronic Inflammatory Disease with Kidney Involvement

“…Multiple low-density lesions on enhanced CT are the most common radiologic finding in IgG4-related TIN, but diffuse bilateral renal swelling may be observed when severe renal failure is a contraindication for the administration of contrast medium. Kidney abnormalities on CT imaging have been observed in nearly 70 % of patients with IgG4-RD (13)(14)(15)(16).…”