Urology Flashcards
What are urinary calculi?
Crystals formed in the renal collecting tracts
o May be deposited anywhere in the urinary tract
o Lifetime incidence is 15% (M>F; 3x)
What can stones be made of?
o Calcium oxalate – weddellite – 75%
o Magnesium ammonium phosphate – struvite – 15%
o Uric acid – 5%
What are calcium oxalate crystals?
o Related to hypercalciuria
§ Absorptive hypercalciuria – excessive calcium absorption from gut
§ Renal hypercalciuria – impaired absorption of calcium from proximal renal tubule
o Related to ethylene glycol poisoning (metabolises to calcium oxalate)
o Hypercalcemia – primary hyperparathyroidism – rare
What is struvite?
Large stones = Staghorn Calculi ^^
o Causes
§ Recurrent UTI -> infection with urease producing organisms – proteus sp.
§ Hyperammonaemia -> ammonia alkalises urine -> precipitation of magnesium phosphate salts
What is uric acid?
o Form in patients with hyperuricaemia (i.e. from gout ± rapid cell turnover)
o Most patients do not actually have hyperuricaemia or increased uric acid excretion in urine
o Believed to be due to tendency to produce slightly acidic urine
What are the complications of urinary calculi?
o Small stones that stay in kidney – largely asymptomatic
§ Otherwise detected during investigation of haematuria or recurrent UTI
o Small stones that drift out of the kidney may become impacted and cause colic – locations to get struck:
§ Pelvo-ureteric (PUJ) junction, pelvic brim, vesico-ureteric junction (VUJ)
o Large stones tend to stay in the kidney – obstruction, risk of infection, chronic renal failure
What is a papillary adenoma?
· Benign epithelial kidney tumour, composed of papules ± tubules
o Well defined – must be 15mm or less (if >15mm = malignant PRCC)
o Well circumscribed
o Trisomy 7, Trisomy 17, loss of Y chromosome
· Frequent incidental finding in nephrectomies and at autopsy
o Especially in chronic kidney disease, acquired cystic renal disease
What is a renal oncocytoma?
· Benign epithelial kidney tumour composed of oncocytic cells
o Well circumscribed – see right image – circular
o Usually sporadic
o Can be seen in Birt-Hogg-Dube syndrome
· Usually incidental finding
What is an angiomyolipoma?
· Benign mesenchymal kidney tumour composed of thick-walled blood vessels, smooth muscle and fat
o Derived from perivascular epithelioid cells
o Mostly sporadic
o Can be seen in tuberous sclerosis
· Usually incidental
o Larger tumours >4cm may present with flank pain, haemorrhage, shock
What is a renal cell carcinoma?
· Accounts for 2% of cancers worldwide
o More common in developed countries, more in men
· RF: smoking, HTN, Obesity, long term dialysis, genetic syndromes (VHL)
· Presentation:
o Painless haematuria (50%) VHL = phaeochromocytoma, neuroendocrine pancreatic
o Incidentally on imaging tumour, clear cell renal cell carcinoma
o Small proportion present with metastatic disease
What is clear cell renal carcinoma?
§ Epithelial kidney tumour composed of metastases of clear cells set in a delicate capillary vascular network – associated with VHL
§ Appears grossly, as a golden yellow tumour with haemorrhagic areas
§ Genetically – shows loss of chromosome 3p
What is papillary renal cell carcinoma?
§ Epithelial kidney tumour composed or papillae ± tubules
· >15mm in size
· Genetically – trisomy 7, trisomy 17, loss of Y
· Divided into 2 types based on morphology
§ Grossly appears as a fragile, friable brown tumour
· Left = type 1 – single layer of flatter cells
· Right = type 2 – more oncolytic cells – do worse
§ Associated with long-term dialysis
What is chromophobe renal cell carcinoma?
§ Epithelial kidney tumours composed of sheets of large cells that display distinct cell borders, reticular cytoplasm and thick-walled vascular network
· Variable genetic aberrations
§ Well circumscribed solid brown tumou
What affects prognosis in RCC?
· 5-year survival across all tumour types is 60%
· Staging and grading (most important prognostic factors):
o Clear cell, papillary:
§ ISUP Nuclear Grade (1-4)
o Clear cell, papillary, chromophobe:
§ TNM 8th edition
· Risk of progression index (Leibovich Risk Model – low risk, intermediate risk, high risk):
o Clear cell renal carcinoma
What is a nephroblastoma?
· Malignant triphasic kidney tumour of childhood
o Blastema – small round blue cells = a feature of primitive tumours (-blastomas)
o Epithelial
o Stromal
· Typically presents as an abdominal mass in children aged 2-5 (2nd most common childhood malignancy, behind ALL)
· 95% of cases show favourable histological features with excellent prognosis