Urological Pathology Flashcards
What are urinary calculi? What is the epidemiology of urinary calculi?
Crystal aggregates that form in the renal collecting ducts.
May be deposited anywhere in the urinary tract.
Lifetime incidence 15%.
Males three times more likely to be affected than females.
What are stones in urinary calculi made of?
Calcium Oxalate (Weddellite) – 75%
Magnesium Ammonium Phosphate (Struvite) – 15%
Uric Acid – 5%
What are calcium oxalate stones related to?
Calcium oxalate stones are related to hypercalciuria.
- Absorptive hypercalciuria: Excessive calcium absorption from gut.
- Renal hypercalciuria: Impaired absorption of calcium in proximal renal tubule.
- Hypercalcaemia: Primary hyperparathyroidism.
Rare
What are triple stones?
Magnesium ammonium phosphate stones are also known as ”triple stones”. Form as a consequence of infection with urease-producing organisms (Proteus sp.).
Ammonia alkalinises urine – precipitation of magnesium ammonium phosphate salts follows. Triple stones can become very large indeed.
What are Staghorn Calculi made of?
Magnesium ammonium phosphate
What is this?
Triple stones
What are uric acid stones?
Uric acid stones may form in patients with hyperuricaemia (Gout). Rapid cell turnover.
Most patients do not actually have hyperuricaemia or increased uric acid excretion in urine.
Believed to be due to tendency to produce slightly acidic urine.
What are complications associated with urinary calculi?
Small stones that stay in the kidney may be largely asymptomatic: Otherwise detected during investigation of haematuria or recurrent urinary tract infection.
Small stones that drift out of the kidney may become impacted and cause colic: Pelvi-ureteric junction, pelvic brim, vesico-ureteric junction.
Large stones tend to stay in the kidney: Obstruction, risk of infection, chronic renal failure.
What are papillary adenomas?
Benign epithelial kidney tumour composed of papillae and/or tubules.
- By definition, 15mm or less in size.
- Well-circumscribed.
- Trisomy 7, Trisomy 17, Loss of Y chromosome.
Frequent incidental finding in nephrectomies and at autopsy, especially in chronic kidney disease, acquired cystic renal disease.
What is this?
Papillary adenoma
What are renal oncocytomas?
Benign epithelial kidney tumour composed of oncocytic cells:
- Well-circumscribed
- Usually sporadic
- Can be seen in Birt-Hogg-Dubé syndrome
Usually an incidental finding.
What is this?
Renal oncocytoma
What is this?
Renal oncocytoma
What are angiomyolipomas?
Benign mesenchymal kidney tumour composed of thick-walled blood vessels, smooth muscle and fat:
- Derived from perivascular epithelioid cells
- Mostly sporadic
- Can be seen in tuberous sclerosis
What are the signs and symptoms of angiomyolipomas?
Usually an incidental finding.
Larger tumours (> 4cm) may present with flank pain, haemorrhage, shock.
What is this?
Angiomyolipoma
What are renal cell carcinomas?
Malignant epithelial kidney tumour.
Accounts for 2% of cancers worldwide.
More common in developed countries.
10 per 100,000 men, 3 per 100,000 women.
What are risk factors for renal cell carcinomas?
Smoking
Hypertension
Obesity
Long-Term Dialysis
Genetic Syndromes – von Hippel Lindau
What are signs and symptoms of renal cell carcinoma?
Half of cases present with painless haematuria.
Most of the remaining cases are detected incidentally on imaging.
Small proportion present with metastatic disease.
What are the various subtypes of renal cell carcinoma?
Clear Cell Renal Cell Carcinoma (70%)
Papillary Renal Cell Carcinoma (15%)
Chromophobe Renal Cell Carcinoma (5%)
Remaining 10% are various rare subtypes
What are clear cell renal cell carcinomas?
Epithelial kidney tumour composed of nests of clear cells set in a delicate capillary vascular network.
Appears grossly as a golden yellow tumour with haemorrhagic areas.
Genetically shows loss of chromosome 3p.
What is this?
Clear Cell Renal Cell Carcinoma
What are papillary renal cell carcinoma?
Epithelial kidney tumour composed of papillae and / or tubules.
- By definition, more than 15mm in size.
- Genetically shows trisomy 7, trisomy 17 and loss of Y chromosome.
- Subdivided into two types based on morphology.
Grossly appears as a fragile, friable brown tumour.
What is this?
Papillary renal cell carcinoma
What is this?
Papillary renal cell carcinoma
What are chromophobe renal cell carcinoma?
Epithelial kidney tumour composed of sheets of large cells that display distinct cell borders, reticular cytoplasm and a thick-walled vascular network.
Shows variable genetic aberrations.
Grossly appears as a well-circumscribed solid brown tumour.
What is this?
Chromophobe renal cell carcinoma
What is the prognosis of renal cell carcinomas?
Five year survival across all tumour types is 60%.
Staging and Grading are most important prognostic factors.
ISUP Nuclear Grade (1-4) applies to clear cell and papillary renal cell carcinoma.
For clear cell renal cell carcinoma there is also a risk progression index.
Leibovich Risk Model (low risk, intermediate risk, high risk).
What is a nephroblastoma?
Also known as Wilm’s Tumour.
Malignant triphasic kidney tumour of childhood.
- Blastema (small round blue cells)
- Epithelial
- Stromal
Typically presents as an abdominal mass in children aged 2-5 years old.
1 in 8,000 – second most common childhood malignancy.
95% of cases show favourable histological features with excellent prognosis.
What are urothelial carcinoma?
Also known as Transitional Cell Carcinomas.
Group of malignant epithelial neoplasms arising in urothelial tract.
- Bladder
- Renal Pelvis
- Ureters
Very common.