Nephroquiz 2: differential diagnoses of mesangial proliferative glomerulonephritis.

CASE A 38-year-old man was admitted to hospital for evaluation of kidney dysfunction. His serum creatinine on admission was 1.6 mg/dL. His past medical history was unremarkable and there was no family history of kidney dysfunction. His blood pressure was 130/80 mm Hg, and he had no history of hypertension. Physical examination revealed only mild pedal edema. On urinalysis, there were microscopic hematuria with dysmorphic erythrocytes and proteinuria. Twenty-four-hour urine collection revealed 1200-mg protein excretion per day. Studies of serum complements, antinuclear antibodies, antineutrophil cytoplasmic antibodies, rheumatoid factor, and hepatitis viral markers had unremarkable results. The size of the kidneys was normal on ultrasonography. Biopsy of the kidney was performed, and light microscopic study of the tissue revealed 10 glomeruli all of which showing mesangial widening with hypercellularity. No obvious endocapillary proliferation or subendothelial deposits were identified (Figure 1). The immunofluorescence study revealed deposition of immunoglobulin A (IgA) and complement 3 (C3) in the mesangial regions (Figure 2). Based on pathologic findings, a diagnosis of mesangiopathic glomerulonephritis with IgA deposition, consistent with IgA nephropathy class III, was established. IJKD 2009;3:172-3 www.ijkd.org