Destructuring glomerular diseases with structured deposits: challenges in the precision medicine era

Excerpt

A 56-year-old man with arterial hypertension, previous history of melanoma with negative follow-up and benign prostatic hyperplasia presented with scrotal edema, subnephrotic proteinuria (2.1 g/die) and microhematuria with an initial decrease in renal function (serum creatinine 1.4 mg/dl). Physical examination and ultrasound showed varicocele as a possible cause of the edema, but further laboratory tests revealed hypocomplementemia (C3 20 mg/dl and C4 3 mg/dl) with negative autoimmunity and viral markers. Renal biopsy showed a glomerulocentric deposition of hyaline, acellular, amorphous material occupying mesangial areas and capillary walls, with slight positivity to PAS stain (Fig. 1a) and negativity to Jones silver stain (Fig. 1b). No vascular nor tubulointerstitial involvement by these deposits was noted. Immunofluorescence on snap-frozen tissue was positive for IgG, with clear cut lambda light chain restriction (Fig. 1c, d).

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