CASE 187 (September 2021)

Case provided by:
Boonyarit Cheunsuchon, MD
Associate professor
Department of Pathology, Siriraj Hospital
Mahidol University
Bangkok 10700 Thailand

Clinical information

The patient is a 41-year-old woman with diabetes, who developed abrupt nephrotic syndrome, for which a kidney biopsy was performed. The biopsy shows advanced diabetic nephropathy without superimposed GN.

There is an area of tubular lesions as in the images:

Figure 1. H&E, X400. Note the tubular material.

Figure 2. Masson's trichrome stain, X400.

Figure 3. PAS, X400.

Figure 4. Methenamine-silver stain, X400.

Direct immunofluorescence showed linear positivity for IgG in tubular and glomerular basement membranes, characteristic of diabetic nephropathy, without any other type of positivity; kappa and lambda with similar staining. Congo red stain: negative.

What are these lesions?

See diagnosis and discussion

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