A 57-years-old man presented with 6 months history of edema in legs with urinary volume disminution. He relate weight loss (7 Kg in 6 months) and dyspnoea with fisical activity.
On physical examination blood pressure was: 110/80; paleness of the skin, and edema in legs. There are not lesions in skin. Otherwise, the physical examination was unrevealing.
Urinalysis revealed no hematuria; proteins 5.50 g/24 h. Seric creatinine was 1.1 mg/dL; creatinine cleareance: 120 mL/min; C3 and C4: normals; ANAs, Anti-DNA, ANCAs, AgSHB, AcVHC, HIV, and crioglobulins: negative. Liver function was normal. Renal sonography show increase in the renal size. Ecocardiography showed concentric ventricular left hypertrophy with a thick septum. Protein electrophoresis (serum): normal.
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What is the differential diagnosis?
A renal biopsy was undertaken. See the images.
Figure 1. (H&E, x400)
Figure 2. (H&E, x400)
Figure 3. (PAS, x400)
Figure 4. (Masson's trichrome stain, x400)
Figure 5. (Congo red stain. Left with conventional light; right with polarized light, X400)
Figure 6. (Congo red stain. Left with conventional light; right with polarized light, X400)
Immunofluorescence for IgA, IgG, C3, C1q, and lambda were negative. There was a mild staining for IgM and light chain kappa in glomeruli and arterioles.
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