Class III Focal Lupus Nephritis

This 9-year-old female was recently evaluated for lymphoid malignancy due to weight loss and intermittent fevers. Following a negative workup for malignancy, further routine studies showed mild hematuria and proteinuria and she was referred to a pediatric nephrologist. The serologic evaluation showed a positive ANA and positive double-stranded DNA, complement C3 borderline low and C4 normal. Urinalysis showed 3-5 RBCs/HPF but no casts with 2+ blood and 1+ protein. Mesangial lupus was suspected but a biopsy was done to rule out activity.

Figure 1 – No fibrosis with diffuse mesangial hypercellularity and focal proliferation but no crescents and no hyaline thrombi (H&E 100x).
Figure 2 – Mesangial matrix expansion and mesangial hypercellularity (Jones silver 400x).
Figure 3 – Endocapillary proliferation in more than three-quarters of the glomerulus. Note the open loops at around 5:00 o’clock (Jones silver 400x).
Figure 4 -Wire loop (arrowhead) in a glomerulus with only mesangial hypercellularity (Silver Methenamine Masson Trichrome or SMMT 400x).

Diagnosis: Focal Lupus Nephritis, Class III (A) with mild activity and no chronicity