Atypical Plasmacytic Proliferation in a Case of C3 Glomerulopathy: Pathophysiology Demystified.

Osama Elfituri,Suman Setty,Nathan Aardsma,Frederick Behm,Kimberly Czech

doi:10.1177/2324709617690746

Osama Elfituri, Suman Setty + Show 3 more

Open Access

https://doi.org/10.1177/2324709617690746

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Abstract

An 11-year-old Hispanic female underwent evaluation of asymptomatic proteinuria and hematuria. The patient denied fever, edema, and gross hematuria. Urinalysis showed mild proteinuria, and a urine microscopic examination revealed red blood cells. Screening tests for glomerulonephritis revealed a low C3 and negative ANA, ASO, DNAse-B, and ANCA. Histological examination of a renal biopsy specimen showed glomeruli with endocapillary proliferation, a predominant C3 deposition in the capillary loops by immunofluorescence, and electron dense deposits in the mesangium, paramesangium, and capillary walls by electron microscopy consistent with a diagnosis of C3 glomerulopathy. An interstitial plasmacytosis was also present with focal clustering of plasma cells, which were found to be kappa light chain restricted by in situ hybridization suggestive of a clonal proliferation. One can speculate that these plasma cells may be directly responsible for the renal pathology that was seen.

Highlights

An asymptomatic 11-year-old Hispanic female was referred to a pediatric nephrologist and found to have proteinuria and hematuria on screening urine analysis
Due to the presence of persistent hematuria (17-21 red blood cells per high-power field), serology was sent for C3/C4, which revealed a low C3 at 11 mg/dL and normal C4 at 15 mg/dL
A renal biopsy demonstrated the presence of a predominantly glomerular deposition of C3 fraction of complement in the mesangium, paramesangium, and glomerular capillary wall associated with a small clonal proliferation of plasma cells

Summary

Introduction

An asymptomatic 11-year-old Hispanic female was referred to a pediatric nephrologist and found to have proteinuria and hematuria on screening urine analysis. Urine microscopic examination revealed 21 red blood cells per high-power field and no casts were reported. Due to the presence of persistent hematuria (17-21 red blood cells per high-power field), serology was sent for C3/C4, which revealed a low C3 at 11 mg/dL (normal C3 >76 mg/dL) and normal C4 at 15 mg/dL.

Results

Conclusion