Membranous Nephropathy in Kimura Disease: A Case Report and Literature Review
- Glomerular Diseases: Case Reports
November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Trials
- Murata, Motoki, Department of Nephrology, Osaka Red Cross Hospital, Osaka, Japan
- Koga, Kenichi, Department of Nephrology, Osaka Red Cross Hospital, Osaka, Japan
- Yahata, Kensei, Department of Nephrology, Osaka Red Cross Hospital, Osaka, Japan
Kimura disease (KD) is a chronic benign granulomatous disease characterized by the formation of indistinct masses in the subcutaneous soft tissues and lymph nodes of the head and neck region. Approximately 20% of patients with KD have renal disease, with 60-80% reportedly having nephrotic syndrome. Membranous nephropathy (MN) is one of the major pathologies of renal diseases in KD; however, the underlying mechanism remains unknown.
We herein present a 28-year-old male diagnosed with KD after biopsy of a left lower eyelid mass 11 years earlier. Two months before his presentation, proteinuria was noted for the first time. He visited our hospital with edema in the lower legs and scrotum. A blood test showed a serum creatinine level of 0.95 mg/dL and serum albumin level of 0.9 g/dL. Urinalysis showed heavy proteinuria (7.22 g/gCr) without hematuria. Renal biopsy revealed spike formation by PAM staining and granular deposits of IgG and C3 in the glomerular basement membrane by direct immunofluorescence microscopy (IF). Electron microscopy showed subepithelial electron dense deposits (EDD). The serum anti-phospholipase A2 receptor (PLA2R) antibody was negative, while IF staining for PLA2R was positive in the glomerular basement membrane. The patient was diagnosed with PLA2R-associated MN.
Target antigens in MN, such as PLA2R, were recently identified in both primary and secondary MN. Our literature review on MN in KD including 14 cases revealed that most cases showed subepithelial EDD without subendothelial EDD (Table). This result strongly suggests the involvement of autoantibodies on the surface of podocytes in its pathogenesis. In the present case, PLA2R staining was positive on the glomerular basement membrane. A literature review revealed that PLA2R staining was only performed on 3 out of the 14 cases investigated, and was positive in 2. Further studies on the antigens responsible are needed to elucidate the underlying pathogenesis.