Nephropathology Since 2006
Case 166
With discussion
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CASE 166 (December 2019)

Clinical information

The patient is a 12-year-old girl with a history of nephrotic syndrome a year earlier, which was treated with steroids, presenting a complete response one month later. Steroids were removed and the patient continued normal until a month ago, when she has edema again and relapse of the nephrotic syndrome is documented. Steroids are restarted at 60 mg/m²/d and renal biopsy is ordered, which can only be done one month later. At the time of the biopsy the uroanalysis was normal, without proteinuria or hematuria.

The autoimmunity and infection studies were negative or normal. Normal serum complement. Serum creatinine was always normal. There has been no hematuria. No arterial hypertension has been detected. At the time of relapse the proteinuria was 90 mg/m²/h, there were hypoalbuminemia (2.2 g/dL) and dyslipidemia.

See the images.

Figure 1. PAS, X400. Almost normal histological features, except for a mild mesangial hypercellularity in some glomeruli. There were no segmental hyaline or sclerosing lesions in any glomerulus.

Figure 2. PAS, X400.

Figure 3. Masson's trichrome stain, X400.

Figure 4. Methenamine-silver stain, X400.

Figure 5. Methenamine-silver stain, X600. Normal capillary walls, without irregularities.

Figure 6. EM, original magnification: X2,100. Normal glomerular capillaries. There is no loss or fusion of peodocyte processes. Thickness of the basement membrane within the normal range.

Figure 7. EM, original magnification: X2,100. Small segments of loss (or fusion) of podocyte processes, as seen in the upper part of the capillary in this image.

Figure 8. EM, original magnification: X3,500. Most capillaries have normal podocitary processes.

Figure 9. EM, original magnification: X3,500.

Figure 10. EM, original magnification: X2,100.

Figure 11. EM, original magnification: X2,100.

Figure 12. EM, original magnification: X3,500. In this more detailed image, the normality of the fenestrated endothelium, the basement membranes and the podocitary processes and slit diaphragm is observed.

Direct immunofluorescence for IgA, IgG, IgM, C3, and C1q: Negative.

What is your diagnosis?

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