Urinary gross and histopathic lesions

What structures are normally present in the kidney?

• glomeruli

• tubules

• collecting ducts

• interstitial connective tissue

  • blood vessels

  • fibroblasts

What structures are normally present in the lower urinary tract?

• transitional epithelium

• smooth muscle

• connective tissue

• blood vessels

what is this structure?

glomerulus

what is this structure?

proximal tubule

How can we tell if its PCT or DCT?

• PCT

  • narrower lumen

  • thicker epithelial cells

• DCT

  • wider lumen

  • thinner epithelial cells

what are these structures?

Distal tubules

What features of glomeruli are important?

• specialised structures

• highly vulnerable to damage

• unable to regenerate

What cell types can be found in the glomerulus?

• podocyte cells - part of filtration barrier, contract to regulate filtration

• mesangial cells - phagocytic to scavenge filtration entrapped debris

What is this structure?

collecting duct

• largest and most robust

• wide lumens

• only found in medulla

What is this structure?

renal pelvis

What is present in the interstitial tissue?

• blood vessels

• fibroblasts

• lymphocytes (occasionally)

What type of cells line the bladder?

transitional epithelial cells

What are these cells?

transitional epithelial cells

what are 4 layers of the bladder wall?

(bladder lumen)

• transitional epithelium

• lamina propria

• muscular layer (detrusor muscle)

• adventitia (with fat cells)

What pathological additions may we see in the urinary tract grossly?

swelling

What pathological additions may we see in the urinary tract histologically?

• inflammatory cells / leucocytes

• exudate / oedema / cell debris

• tumour cells

• fibroblasts (for repair)

• aetiological agents e.g. bacteria

What histopathological losses may we see to the urinary tract?

• necrosis —> creates spaces

• glomerular and tubular fibrosis —> collagen contracts so we see shrinkage

What would the effect be of glomerular fibrosis?

glomerulus and nephron non-functional

What if the effect of tubular necrosis?

• if basement membrane intact

  —> regeneration of epithelium

• if basement membrane not intact

  —> regeneration not possible (to 100%)

  —> repair with fibrosis

  —> collagen contracts so see shrinkage e.g. chronic infarct

describe the gross lesion

• organ is the kidney

• pale pink/orange colour change

• capsular surface is bumpy

• raised multifocal to coalescing yellow/orange nodules on capsular surface - pus filled

• medulla is pinky white (should be pale brown)

• medulla is more firm than usual

describe the capsular surface

capsular surface is not smooth

describe the tubular changes

dilated lumen of tubules in cortex and medulla

radially distributed (in lines)

what can we see on this medium power histology view of kidney?

• tubules with eosinophilic amorphous material in the lumen = protein in filtrate

• arrow points to cell debris within lumen

• lack of glomeruli

• purple stippling in the interstitium - inflammatory cells

what can we see on this high power histology view of kidney?

• red/pink strands within interstitium = collagen

• tubules are being squashed / flattened

• fibroblasts (elongated strand like cells) with the collagen

• plasma cells and lymphocytes in the middle

• macrophages present (larger potato shaped cells)

what would the disease and morphological diagnosis be, based off the following clinical signs and pathological features?

• chronic PUPD

• pale pink bumpy/nodular capsular surface of kidney

• medulla pale pink and firm

• collagen in interstitial tissue

• inflammatory cells present in interstitium

• debris and protein present in lumen of tubules

• disease = chronic kidney disease

• morphological diagnosis = fibrous interstitial nephritis with tubule dilation

describe the gross changes to this kidney

• organ is kidney

• pale tan discolouration to cortex, and diffuse creamy white discolouration of medulla

• consistency is firm

what can we see on this low power histology view of kidney?

• dilated tubules / blood vessels

• fine purple stippling = possibly inflammatory cells

what can we see on this medium power histology view of kidney?

• cell debris within lumen of tubules —> necrosis of epithelial cells

• multifocal areas with crystalline structures within lumen of tubules

what can we see on this high power histology of kidney?

crystals within lumen of tubules - some granular and some stellate (star formation)

what would the disease and morphological diagnosis be based off the following clinical signs and pathological changes?

• history = acute collapse and anuria

• creamy white discolouration of medulla

• blocking of tubule lumen with crystals

• necrosis of epithelial lining of tubules

morphological diagnosis = acute diffuse severe mineralising nephropathy

disease = ethylene glycol toxicity

describe this gross lesion

• mineralisation / masses (5mm x 5mm) in medulla of kidney —> calculi

• calculi firm in consistency and pale tan colour

• dilated tubules within medulla, extending slightly into cortex —> starting to become cystic

• dilation of renal pelvis —> hydronephrosis

• pressure atrophy of cortex and medulla

what can we see on this low power histology of kidney?

• purple / black area in medulla - likely in tubule or collecting duct

• red staining in cortex —> hyperaemia of blood vessels

• purple stippling = inflammatory cells at the bottom of the image - radial pattern to purple stippling

what can we see in this medium power histology of kidney?

• purple stippling = inflammatory cells

• tubules containing pink amorphous material = filtrate containing protein

• dilation of tubules

what can be seen on this high power histology of kidney?

• dilation of tubules with eosinophilic material in lumen = protein within filtrate (but distribution of protein in the fluid is uneven)

• pale pink strands and elongated nuclei = fibroblasts

• glomeruli lacking nuclei on bottom left of image- being replaced by collagen —> glomerulus cirrhosis due to fibrous tissue

• inflammatory cells - lymphocytes and plasma cells in middle of image

what would the disease and morphological diagnosis be based off the following clinical signs and pathological changes?

• history = haematuria (blood in urine) and dysuria (difficulty urinating)

• dilation of renal pelvis + calculi present

• dilated tubules + tubule lumens with protein in filtrate

• fibroblasts present in interstitium

• glomeruli lacking nuclei with collagen forming

• inflammatory cells = lymphocytes and plasma cells

morphological diagnosis = chronic fibronecrotising pyelonephritis with proteinuria

disease = pyelonephritis due to local trauma from calculi

what can we see in this gross image of kidney?

• multifocal 1mm pale tan lesions across the surface of kidney

• kidney is diffusely red and swollen

what can we see in this low power histology of kidney?

• cortical surface is not smooth

• structures with central eosinophilic staining with purple stippling around the border

what can we see in this medium power histology of kidney?

• on the left of the image there are tubules with pale eosinophilic amorphous material = protein in filtrate

• in the middle of the image there are tubules with squashed / flattened lumen

• right of the image shows nodule containing lots of fine purple stippling and eosinophilic material

what can we see in this high power histology of kidney?

• increased cellular density

• bottom left - cells with large potato shaped nuclei = macrophages, multi-nucleated giant cells

• top right - fragmented nuclei, eosinophilic material merging together = cell debris —> necrosis

what would the disease and morphological diagnosis be based off the following clinical signs and pathological changes?

• history =

• red swollen kidney with multifocal tan lesions

• macrophages and multi-nucleated giant cells present

• areas with concentrated cell debris and necrosis present

morphological diagnosis = chronic severe necrogranulomatous interstitial nephritis

disease = migrating parasite e.g. Toxocara canis