Membranous-like glomerulopathy with masked IgG-k deposits in a pediatric patient with juvenile idiopathic arthritis.
Priyanka Chati, Jill Krissberg, Kammi Henriksen et al.
✦ AI-curated · Sources linked
Case in brief
A 12-year-old girl with systemic juvenile idiopathic arthritis had persistent proteinuria despite normal kidney function. Her first kidney biopsy suggested mild C3 glomerulonephritis. Proteinuria later reached the nephrotic range, and it persisted despite ACE-inhibitor therapy, high-dose steroids with taper, and mycophenolate. A repeat biopsy established membranous-like glomerulopathy with masked IgG-kappa deposits. She remained on mycophenolate and lisinopril, with significant improvement in proteinuria.
What made this case unusual
The initial biopsy suggested C3 glomerulonephritis, whereas a repeat biopsy identified MGMID, illustrating a diagnostic discrepancy in a child with systemic juvenile idiopathic arthritis and persistent proteinuria.
Diagnostic / clinical pearl
When proteinuria persists despite treatment and the initial biopsy does not explain the clinical course, reassessment with repeat kidney biopsy may reveal a different glomerular diagnosis.