CRP-28

CRP-28

Clinical History

The patient is a 58 year old male. Positive anti-dsDNA (221). Creatinine 0.6, creatinine clearance 104 ml/min, urinary protein 1.125 g/day. C3 = 44, C4 = 4.

Gross Description

Received in Zeus fixative are three cores measuring 3, 10 and 11 mm in length and 1 mm in diameter. These are entirely submitted for immunofluorescence. Received in Carson's fixative are three cores measuring 12, 14 and 17 mm in length and 1 mm in diameter. Six 1-mm pieces are taken for EM, and the remaining tissue is submitted for light microscopy.

Pathology

Case CRP-028 Silver

Microscopic Description, Immunofluorescence, and Electron Microscopy

Microscopic Description

Light Microscopy

The specimen consists of two fragments of renal medulla and three fragments of renal cortex. There are seventy-eight glomeruli in the three levels, which present a range of morphology. Seven are globally sclerotic, six demonstrate segmental sclerosis two contain cellular crescents, and twenty-seven show segmental necrosis. The remaining glomeruli show minimal mesangial expansion and proliferation. The silver stain shows occasional capillary loops with subendothelial deposits, but there is no splitting of the basement membranes. No spikes are noted along the epithelial surfaces. The PASH and trichrome stains show mild focal interstitial fibrosis and tubular atrophy. There is no interstitial edema, and there is no interstitial inflammation. The vasculature is well sampled and is unremarkable.

Immunofluorescence

There are eleven glomeruli in the sections. None of these are obsolete. There is diffuse granular mesangial staining that is graded 2+ for IgG, IgM, IgA, Clq, C3 and Kappa. There is 1+ mesangial staining for lambda. There is focal and segmental l+ staining along the capillary loops for all of these reagents. There is no staining of the vessels. Tubular basement membranes show focal 1+ staining for IgG and light chains. Tubular epithelial nuclei are strongly positive for IgG and light chains.

Electron Microscopy

Three thick sections containing a total of three glomeruli are available. Two show segmental necrosis. Ultrastructural examination reveals mild increase in mesangial matrix, although numerous mesangial electron dense deposits are identified. The capillary basement membranes are focally thickened, and there is focal fusion of the foot processes. The loops in the necrotic segments contains numerous large subendothelial deposits, and occasional smaller subendothelial deposits are noted in other loops. No subepithelial or intramembranous deposits are noted.

Diagnosis and Comments

Kidney, needle biopsy - Focal necrotizing and sclerosing lupus nephritis, WHO class 3-B.

These features are most consistent with focal necrotizing and sclerosing lupus nephritis, which corresponds to WHO Class 3-B. The lesion is quite active, as shown by the numerous examples of segmental necrosis as well as subendothelial deposits. Unfortunately, the extent of segmental glomerular necrosis suggests that widespread segmental glomerulosclerosis is inevitable. However, there is currently only mild tubulointerstitial scarring.

A normal gamma-glutamyl transpeptidase (GGT) is 0 to 65 U/L.