CRP-24

CRP-24

Clinical History

The patient is a 29 year old female with probable lupus nephritis. Mild proteinuria and normal renal function.

Gross Description

Received in Zeus fixative are two cores measuring 7 and 8 mm in length and 1 mm in diameter. These are entirely submitted for immunofluorescence. Received in Carson's fixative are three cores measuring 6, 7 and 8 mm in length and 1 mm in diameter. Three 1-mm pieces are taken for EM, and the remaining tissue is submitted for light microscopy.

Pathology

Case CRP-024 PASH

Microscopic Description, Immunofluorescence, and Electron Microscopy

Microscopic Description

Light Microscopy

The specimen consists of three cores of renal cortex that contain 40 glomeruli in the three levels. Two of these are obsolete, and four show segmental sclerosis with adhesions to Bowman's capsule. The remaining glomeruli are all similar and show minimal mesangial expansion and focal very mild mesangial cell proliferation. There is no segmental proliferation. The silver stain shows basement membranes of normal thickness, although occasional small holes are noted in enface cuts through the basement membranes. There is mild interstitial fibrosis, but there is minimal tubular atrophy. A number of the tubules are dilated, and the epithelium shows mild simplification. However, no red cells or cellular debris are noted within the tubular lumina. There are no inflammatory infiltrates. The small arteries show mild intimal fibrosis, but are otherwise unremarkable.

Immunofluorescence

There are six glomeruli in the sections. None of these show segmental sclerosis, and none are obsolete. There is diffuse mesangial staining that is graded 1+ for IGG, C1q and kappa and lambda light chains. There is similar mesangial staining that is graded only trace for IgM, IgA, and C3. There is no staining of the capillary basement membranes. There is no staining of the tubular basement membranes or vessels.

Electron Microscopy

Three thick sections containing a total of six glomeruli are available. One of these contains a focus of segmental sclerosis, and another shows severe global atrophy and sclerosis. The other four are similar to those described above and show minimal mesangial expansion and hypercellularity. Ultrastructural examination reveals occasional small, ill-defined mesangial electron dense deposits. The capillary basement membranes are generally of normal thickness and there is only focal effacement of the epithelial cell foot processes. No subepithelial, intramembranous or subendothelial deposits are identified in the capillary basement membranes.

Diagnosis and Comments

Kidney, needle biopsy - Mesangial lupus nephritis, WHO Class II.

These findings are most consistent with mild mesangial lupus nephritis, WHO Class II. There is no evidence for transition to a more active lesion. There is minimal irreversible tubulointerstitial damage.

Protein in the urine is indicative of glomerular dysfunction.

An infiltrate is an accumulation of cells in the lung parenchyma--this is a sign of pneumonia.