Diagnose This (March 12, 2018)

What is your diagnosis?

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The photomicrographs show marked mesangial matrix expansion without nodule formation, almost absent silver impregnation in the mesangial matrix and smudgy, mesangial IgG deposits by immunofluorescence. This morphology is highly suggestive of fibrillary glomerulopathy, however with the information given a definitive diagnosis cannot be made. Definitive diagnosis of fibrillary glomerulopathy has traditionally been performed on electron microscopy where the presence of randomly oriented, non-branching fibrils can be seen in the mesangium, capillary wall or both. However, with the recent introduction of DNAJB9 staining (a highly sensitive and specific stain for fibrillary, see reference and below) this may be augmented over time.

Reference: https://www.ncbi.nlm.nih.gov/pubmed/29340314