Nephroquiz 3: nephrotic syndrome in adult patients with skin lesions.

CASE A 52-year-old man presented with malaise and weakness associated with edema and nephrotic range proteinuria. He also had arthralgia and myalgia. Serum creatinine level was between 2 mg/dL and 2.5 mg/dL. Physical examination revealed purpura on the extremities and also on the abdominal skin. Laboratory studies revealed high serum cholesterol and triglyceride levels. He also was anemic (haemoglobin level, 8 g/dL to 10g/ dL). Serum complements including C3 and C4 and also CH50 had decreased. Serum antinuclear antibody, anti-double-stranded-DNA, and antineutrophil cytoplasmic antibody were negative. A percutaneous kidney biopsy containing 17 glomeruli showed marked endocapillary hypercellularity with lobular accentuation characterized by mesangial cell proliferation and leukocytes infiltration (Figure 1). Thickening of the glomerular basement membrane was evident with double contour appearance in silver-stained sections (Figure 2). Most of the glomeruli contained amorphous, eosinophilic, fuschinophilic positive deposits, totally filling the capillary lumina (intraluminal thrombi; Figure 3). A few glomeruli showed karyorrhexis and features suggestive of fibrinoid necrosis. The interstitium was edematous with tubular atrophy in about 10% to 20% of the specimen and lymphocytic infiltration in the scarred area. Immunofluorscent evaluation showed intense massive staining of immunoglobulin G (IgG), immunoglobulin M (IgM), and C3 with huge deposits filling the capillary lumen (Figure 4). Considering above findings a diffuse proliferative glomerulonephritis suggestive of a cryoglobulinemic glomerulonephritis was diagnosed. The patient underwent plasma exchange together with cyclophosphamide and corticosteroid therapy. Serum creatinine decreased to about 1.6 mg/dL and urine protein to about 1.5 g/24 hours after 4 weeks. Viral markers, including antihepatitis C virus antibody, were evaluated and were negative. IJKD 2009;3:249-51 www.ijkd.org 1Department of Pathology, Hasheminejad Kidney Center, Iran University of Medical Sciences, Tehran, Iran 2Division of Nephrology, Department of Medicine, Hasheminejad Kidney Center, Iran University of Medical Sciences, Tehran, Iran