View source for CRP-52

'''CRP-52'''
==Clinical History==
The patient is a 66 year old male. BUN 47, creatinine 4.7.

==Gross Description==
Received in Zeus fixative are two cores measuring 7 and 20 mm in length and 1 mm in diameter. These are entirely submitted for immunofluorescence. Received in Carson's fixative are four cores measuring 9, 8, 13, and 4 mm in length and mm in diameter. Three 1-mm pieces are taken for EM, and the remaining tissue is submitted for light microscopy.

==Pathology==
===Case CRP-052 H&E===
<peir-vm>specialcrp/CRP-052_HE</peir-vm>
===Case CRP-052 PASH===
<peir-vm>specialcrp/CRP-052_PASH</peir-vm>

<div class="usermessage mw-customtoggle-diagnosis" style="cursor:pointer"> Microscopic Description, Immunofluorescence, and Electron Microscopy.</div>
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==Microscopic Description==
===Light Microscopy===
The specimen consists of multiple small fragments of renal cortex that contain twenty glomeruli in the three levels.  Three of these are globally sclerotic, but the remainder show good preservation with no significant mesangial expansion or hypercellularity. The glomerular basement membranes are unremarkable with the silver stain. The PASH and trichrome stains show diffuse moderate interstitial fibrosis and focal tubular atrophy. However, there is also diffuse interstitial edema with numerous mononuclear inflammatory cells. The infiltrate is composed primarily of lymphocytes with occasional plasma cells and rare eosinophils. Many examples of tubulitis are identified. Several arteries show severe intimal fibrous thickening.

===Immunofluorescence===
There are four glomeruli in the sections. Stains for IgG, IgM, IgA, Clq, C3, albumin and light chains are negative in the glomeruli. There is no staining of the tubular basement membranes or vessels.

===Electron Microscopy===
Three thick sections containing a total of two glomeruli are available. Ultrastructural examination of one glomerulus reveals no significant mesangial expansion or hypercellularity. The glomerular basement membranes are of normal thickness, and the foot processes are intact. No electron dense deposits are identified. Numerous examples of emperipolesis are identified in the proximal tubules.

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<spoiler text="Diagnosis and Comments">
Kidney, needle biopsy 
- Acute tubulointerstitial nephritis.

- Severe arteriosclerosis with moderate interstitial fibrosis.

These features are most: consistent with acute tubulointerstitial nephritis. However, there is also a background of moderately severe interstitial fibrosis, probably secondary to arteriosclerosis. Although eosinophils are relatively rare in this biopsy, this does not rule out a drug-induced allergic interstitial nephritis.
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