CRP-50
CRP-50
Clinical History
The patient is a 70 year old female. History of Relafen usage with recent increase in dosage. BUN 98, creatinine 3.7, urinary protein 7.7 g/24 hr. Creatinine clearance 11.6 ml/min.
Gross Description
Received in transport media are two cores measuring 11 and 9 mm in length and 2 mm in diameter. Two 1-mm pieces are taken for EM, and the remainder is bisected and divided equally for immunofluorescence and light microscopy.
Pathology
Case CRP-050 H&E
Case CRP-050 PASH
Microscopic Description
Light Microscopy
The specimen consists of two fragments of renal cortex that contain twenty-three glomeruli in the three levels. One of these is obsolete, but none show segmental sclerosis or adhesions to Bowman's capsule. All of the glomeruli show mild increase in mesangial matrix, but there is no significant mesangial hypercellularity. The capillary basement membranes are unremarkable with silver and PASH stains. There is mild patchy fibrosis, but there is also moderate interstitial edema. Tubular atrophy is minimal. However, a number of the tubules show marked irregular dilatation, epithelial simplification and degenerative epithelial changes, consistent with acute tubular necrosis. Occasional mononuclear inflammatory cells are present in the interstitium, but tubulitis is not noted. Most of the damaged tubules contain sloughed epithelial cells in the lumen, and a few also contain calcium oxalate crystals. Arterioles show mild thickening, but the larger vessels show minimal intimal fibrous thickening.
Immunofluorescence
There are eleven glomeruli in the sections. Two of these are obsolete. There is trace mesangial staining for IgM, but stains for IgG, IgA, C1q, C3 and light chains are negative in the glomeruli. Tubular epithelium contains numerous protein droplets that stain for albumin, C3 and light chains. There is no staining of the tubular basement membranes or vessels.
Electron Microscopy
Two thick sections containing a total of five glomeruli are available. These are similar and show mild mesangial expansion without proliferation. Tubules show changes consistent with acute necrosis. Ultrastructural examination reveals minimal thickening of the capillary basement membranes, although there is diffuse fusion of the epithelial cell foot processes No electron dense deposits are identified in the glomeruli. Tubular epithelium shows focal degeneration and loss of the epithelial brush border.