CASE 200 (October 2022)

Clinical information

A 58-year-old woman with no medical history was admitted because of legs edema with proteinuria and hematuria. Urinalysis showed a proteinuria level of 2.8 g/24 h and 15-20 red blood cells/hpf. Serum creatinine; 1.9 mg/dL, BUN: 28 mg/dL; total serum protein level: 5.6 g/dL; serum albumin: 3.0 g/dL. Serum C3: 76 mg/dL (88-160 mg/dL), C4: 18 mg/dL (14-40 mg/dL). Normal blood count. Hepatobiliary function was normal. Tests for hepatitis B and C, HIV, ANA, anti-DNA, ANCA: Negative.

A kidney biopsy was taken. Look at the images:

Figure 1. H&E, X400. Endocapillary hyercellularity.

Figure 2. H&E, X400. Lobulation.

Figure 3. Methenamine-silver stain, X400. Some thickened capillary walls and some double contours.

Figure 4. Methenamine-silver stain, X400.

Figure 5. Masson's trichrome stain, X400. Intracapillary hyaline accumuli ("hyaline thrombi").

Figure 6. Masson's trichrome stain, X400.

Figure 7. Masson's trichrome stain, X400. Subendothelial fuschinophilic deposits.

Figure 8. Direct immunofluorescence for IgM, X400. Mesangial and parietal deposits.

Figure 9. Direct immunofluorescence for kappa light chain, X400. Mesangial and parietal deposits.

Figure 10. Direct immunofluorescence for lambda light chain, X400. ~Negative.

Figure 11. EM, original magnification, X2,500. Unorganized subendothelial electron-dense deposits.

Figure 12. EM, original magnification, X2,500. Subendothelial deposits and occasional subepithelial deposits. There are also some unorganized mesangial deposits (not shown in this image).

Figure 13. EM, original magnification, X4,000.

Direct immunofluorescence for IgA, IgG and C1q: Negative. C3: weak parietal and mesangial positivity.

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