CASE 55 (September 2010)
A previously asymptomatic 55-year-old man was evaluated for a 2-months history of legs edema, progressive dyspnea and oliguria. Initial laboratory tests detected severe serum creatinine increase and hyperkalemia. It was considered urgent dialysis.
Blood pressure: 100/60; heart rate: 100; O2 saturation: 95%. There was not organomegaly. He was confused and somnolent. Serum creatinine: 14.8 mg/dL; potassium: 7.7 meq/L; Ph: 6.98; HCO3: 5.2 mEq/L; PaO2: 81.5 mmHg; PaCO2: 22.4 mmHg.
Serum complement: normal. ANA and anti-DNA: negative. HIV and viruses B and C: Negative. Mild normocytic normochromic anemia. Platelets: 105,000/mm3. Cryoglobulins: negative.
Without a clear clinical impression a renal biopsy was performed.
See the images.
Figure 1. H&E, X200.
Figure 2. H&E, X400.
Figure 3. H&E, X400.
Figure 4. H&E. Left X400, right X200.
Figure 5. Masson's trichrome stain, X400.
Figure 6. Masson's trichrome stain, X400.
Figure 7. Masson's trichrome stain. Left X200, right X400.
Figure 8. Masson's trichrome stain, X400.
Figure 9. Methenamine-silver stain, X400.
Figure 10. Methenamine-silver stain, X400.
Figure 11. Direct immunofluorescence using anti-Kappa light chain, X400.
Figure 12. Direct immunofluorescence using anti-Kappa light chain. Left X200, right X400.
Figure 13. Direct immunofluorescence using anti-ambda light chain, X400.
What is your diagnosis?