CRP-40

CRP-40

Clinical History

The patient is a 55-year-old African American man with HIV, history of hypertension and chronic renal insufficiency. Further decrease in renal function (creatinine 6.4; 2.7 3 days previously).

Gross Description

Received in Carson's fixative are two needle cores that measure 10.0 and 11.0 mm in length and 1.0 mm in diameter. Four 1.0 mm pieces are separated for ultrastructural studies and the remainder is processed for light microscopy. An additional core measuring 12.0 x 1.0 mm is received in Zeuss fixative and is processed for immunofluorescence microscopy.

Pathology

Case CRP-040 Trichrome

Microscopic Description, Immunofluorescence, and Electron Microscopy.

Microscopic Description

Light Microscopy

Sections are of four needle core pieces of renal cortex. Two of these include segments of the renal capsule and the largest piece contains a sample of the superficial medulla. There are fifty-nine glomeruli counted, thirty-eight of which obsolete. The viable glomeruli show variable mesangial matrix increase and segmental sclerosing and hyalinosing lesions in nine of the twenty-one viable glomeruli. Several of these lesions show features of lobular collapse, some with modest visceral epithelial cell hypertrophy. There are no necrotizing lesions nor crescents. The tublulointerstitium shows significant interstitial widening with wide spread chronic inflammation. There is severe tubular atrophy, commensurate with the degree of glomerulosclerosis. Multiple examples of microcystic dilatation of lobules are noted. The vasculature is well sampled and shows moderate to severe concentric thickening of the small arteries (inter and intralobular), suggestive of chronic hypertensive injury, as well as moderate segmental thickening of arterioles. There are no thrombotic or vasculitic lesions.

Immunofluorescence

Twelve glomeruli are available for study, six of which are obsolete. Viable glomeruli show local and segmental coarse granular staining of the mesangium for IgM (1-2+), C3 (3+), C1q (2+), and kappa light chain (2+). IgG, IgA, albumen and lambda light chains are negative. There is no significant staining of the tubulointerstium or vasculature.

Electron Microscopy

Six glomeruli are present in the four tissue pieces processed for EM, five of which are globally sclerosed. A single viable glomerulus is studied ultrastructurally, and shows variable mesangial matrix increase, irregular thickening and collapse of the glomerular basement membranes and prominent, widespread effacement of the visceral epithelium. There are scattered hyaline-type protein deposits, but no immune complex deposits are identified.

Diagnosis and Comments

Kidney, left, needle biopsy: • HIV nephropathy with advanced nephrosclerosis. • Hypertensive vasculopathy, moderate.

The biopsy shows classic features of advanced HIV nephropathy. This is superimposed on significant hypertensive vasculopathy. No evidence of an immune complex glomerulonephritis is found.

Aortic insufficiency refers to the inability of the aortic valve to close properly, thus allowing regurgitation of blood into the left ventricle during diastole -- i.e., volume overload. Disease of the aortic valve leaflets is a common cause of insufficiency.