Kidney autopsy

Author: Mikael Häggström

Comprehensiveness

On this resource, the following formatting is used for comprehensiveness:

• Minimal depth
• (Moderate depth)
• ((Comprehensive))

Autopsy cutting

A fine granular surface can be reported as nephrosclerosis, and is associated with arteriosclerosis and glomerulosclerosis.

In non-forensic autopsy, on each side:

• After evaluating the adrenal gland, dissect the renal fascia and perirenal fat laterally, and make an incision in the renal capsule. The renal capsule can then generally be loosened by hand. Note the surface texture. (Determine the color and consistency of the kidney.)
• Dissect the kidney in the coronal plane, towards the hilum. Inspect the cut surfaces.

Gross report

The kidneys are equally sized / (of normal size, with a total weight of ___ g)((a weight of ___ g on the right side and ___ g on the right)).

Sex	Weight, reference range
	Right kidney	Left kidney	Total
Men	80–160 g (2.8–5.6 oz)	80–175 g (2.8–6.2 oz)	160-335g (5.6-12.8 oz)
Women	40–175 g (1.4–6.2 oz)	35–190 g (1.2–6.7 oz)	75-365g (2.6-12.9 oz)

(No abnormal adhesions between the kidneys and surrounding fibrous capsules.)
The kidneys have smooth surfaces/ {{<<Finely / Coarsely>> granular brown surface, possibly indicating benign nephrosclerosis. There are a few cysts on the surface containing clear fluid}}. Cut surfaces have well-defined medulla, cortex, and papillae. {{The cortices and/or medullas are narrowed and congested. The papillary portions are intact.}}
The renal pelvis and ureters are unremarkable /( Renal pelvis and ureters have normal calibers, with non-irritated mucosal surfaces and open lumens).

Fixation

Generally 10% neutral buffered formalin.

  See also: General notes on fixation

Microscopic evaluation

Kidney with substantial autolysis, but otherwise being unremarkable.

The lining of a simple cyst, with inconspicuous nuclei. They usually have a single layer of cuboidal, flattened or atrophic epithelium, but this case has a somewhat thicker fibrous layer.

Findings

The main findings to look for:

Glomerular findings

• Diffuse and/or nodular mesangial deposits:

• 

  Nodular glomerulosclerosis, prompting a consideration of diabetic nephropathy, see section below.

• 

  A glomerulus with total hyalinization (also called a globally sclerotic glomerulus). People aged ≤40 should have less than 1% - 10% globally sclerotic glomeruli, and less than 30% by age 80. An increased amount indicates mainly hypertensive nephropathy, see section below.

• Mesangial hypercellularity (which has been defined as more than 3 cell nuclei per peripheral mesangial area on a 4-μm thick tissue section), prompting a consideration of diabetic nephropathy, see section below.
• Endocapillary hypercellularity, prompting a consideration of diabetic nephropathy, see section below.
• Glomerular basement membrane thickening and/or duplication, prompting a consideration of diabetic nephropathy, see section below.

• 

  Proteinaceous material in Bowman's space, see Proteinaceous material in Bowman's space

• Thrombi

• 

  Thrombi (arrows) and glomerular crescent formation (dotted enclosure, in rapidly progressive glomerulonephritis, in this case due to SLE).

Tubulointerstitial findings

• Interstitial inflammation
• Cytologic atypia in the tubular epithelial cells
• Crystals
• Atypical or pigmented casts

• 

  Distal tubular casts (in addition to interstitial inflammation and fibrosis in myeloma cast nephropathy).

Vascular findings

• Thrombi
• Mural deposition of amorphous material
• Vasculitis
• Congestion

• 

  Intimal thickening with an onion skin-like appearance, indicating mainly hypertensive nephropathy, see section below.

• 

  Histopathology of arteriolar hyalinosis, being a component of nephroarteriolosclerosis, also indicating mainly hypertensive nephropathy, see section below.

• 

  Histopathology of vasculitis (in systemic sclerosis): fibromuscular intimal proliferation and adventitial fibrosis

• 

  Glomerulus with congestion, being an unspecific postmortem finding.

Diagnoses

If indicated by findings above:

Diabetic nephropathy

Nodular acellular light purple glomerular matrix deposits, typical of diabetic nephropathy.

For alterations in glomerular matrix and/or cellularity, the most common cause is diabetic nephropathy, and typically presents as glomerular enlargement, mesangial sclerosis, basement membrane thickening and and arteriolar hyalinosis.

Hypertensive nephropathy

Hypertensive nephropathy has two types:

• Benign hypertensive nephrosclerosis: Characterized by arterial or arteriolar hyalinosis, intimal fibrosis, or medial hypertrophy.
• Malignant hypertensive nephrosclerosis: Characterized by fibrinoid necrosis (acute stage) or myointimal cell proliferation, usually with an “onion-skinning” appearance (chronic stage).

Hypertensive nephropathy, showing fibrous intimal thickening (arrow), interstitial fibrosis, tubular atrophy with thickened tubular basement membranes.

Report

• Findings and if they are consistent with already known diagnoses.

Further information: Autopsy

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