4_primer_mankad_hoey_20150316195755 Flashcards
(168 cards)
Renal Embryology
Kidneys form from pro-, meso- and metanephros; first two regress and only latter persistsUreteric bud from outgrowth of mesonephric ductForm in sacrum and migrate caudally by 8 weeks gestation; maturation continues to 5 y/o
US Medulla Cortex
Renal medulla hypoechoic to cortex
Renal Mass CT protocol
NoncontrastCorticomedullary phase (25-30 seconds)Nephrographic phase (80 seconds)
Location Septum of Bertin
90% upper pole, 60% bilateral Associated with bifid renal pelvis
Congenital megacalyces
Excess of enlarged calyces (20-25 vs normal 10-14), causing hypoplastic pyramidsNo obstruction, normal renal parenchyma and function
Pyelocalcyceal Diverticulum Types
Outpouching of calyx into corticomedullary region; usually asyptomatic but may cause calculiType 1: from minor calyxType 2: from infundibulumType 3: from renal pelvis
ADPKD
Cystic dilatation of collecting tubules and nephrons; 0.1% population, 10% dialysis patients, strong penetranceHepatic cysts (70%), intracranial berry aneurysms (20%), pancreatic and splenic cysts 60 y/o
Acquired cystic kidney disease
Multiple renal cysts developed in CRF; occur in 90% patients on dialysis3-5 cysts in each kidney, CRF and no history of inherited cystic diseaseHemorrhagic cysts occur in 50%, can ruptureRCC develops in 7%
Bosniak criteria
- Benign simple cyst, don’t communicate with collecting system2. Minimally complicated, benign but with concerning featuresThin septations (20) 2F. Multiple septa with or without perceptible but not measurable enhancement; can have thick or nodular calcification, also included if hyperattenuating and >3 cm3. Complicated, multiloculated but with malignant features. 4. Clearly malignant with large cystic component
Medullary cystic disease
Due to tubulointerstitial fibrosisPresents with anaemia and renal failureSmall kidneys with multiple small medullary cysts, often merely causes medullary increased echogenicity, thinned cortexThree typesFamilial nephronophthisis (70%): AR, juvenile onset at 3-5 years but also adult typeAdult medullary cystic disease (15%): AD inheritanceRenal retinal dysplasia (15%): recessive, associated with retinitis pigmentosa
Causes of Nephrocalcinosis
Metastatic (normal kidneys), dystrophic (injured tissue) or urine stasisHyperparathyroidism (primary and secondary)Metastatic carcinoma to bone and hypercalcaemia of malignancyProlonged immobilisationSarcoidosisMilk alkali syndromeHypervitaminosis DRTA (often dense medullary calcification)Medullary sponge kidney (urine stasis)HyperoxaluriaBartter’s syndromeProlonged frusemide (usually premature infants)Nephrotoxic drugsPapillary necrosis
Medullary sponge kidney
AKA Benign renal tubular ectasia, Cacchi-Ricci diseaseDysplastic cystic dilatation of papillary / medullary portions of collecting ducts, usually 20-40 y/o75% bilateral, often asymptomatic; 10% develop progressive renal failureIVP - striated nephrogram (brushlike), ‘bunch of flowers’ appearanceAssociations: Hemihypertrophy, Beckwith-Wiedemann, Pyloric stenosis, Ehlers Danlos, RTA, any form of renal cystic disease / ectopia,
RCC Types
Best evaluated in nephrographic phase, venous invasion best characterised by MRIUS: 70% hyperechoic if > 3 cm, 30% if
Oncocytoma
From epithelial cells of proximal tubule, usually well-differentiated and benign but need resectionCentral stellate scar (25-33% on CT) and spoke wheel (angiography), usually homogeneous enhancement, can’t differentiate from RCC on imaging, but FNA can discriminate
Staging RCC
I: kidney onlyII: extrarenal ± adrenal involvement, but confined within Gerota’s fasciaIII: A - renal vein, B - lymph node metastases, C - bothIV: A - direct extension to other organs through Gerota’s fascia; B - metastases (lung (55%) > liver > bone > adrenal > contralateral kidney (10%))
Renal lymphoma
Occurs in 8% lymphoma patients, 75% bilateral, NHL > HL.Characteristically, renal vessels remain patent despite encasementMR: hypointense to cortex on T1W, heterogeneously hypo to isointense on T2WPatterns (five):Mulitple renal masses (59%)Solitary mass (3%)Renal invasion (contiguous RP spread)Perirenal (10%)Diffuse renal infiltration (rare)
Renal metastases
Fifth most common metastatic site, mainly haematogenous spreadLung, breast and contralateral kidneyColonic metastases often solitary and exophyticMelanoma metastases often have perinephric extension
Angiomyolipoma
Benign hamartomas - blood vessels, smooth muscle, fat; DO NOT contain calcificationCan cause pain, haematuria, anaemiaUsually multiple in tuberous sclerosis (80% of TS have AML)Sporadic form commonest (80-90%): F/M = 4/1, usually middle aged; thus 4 cm often resected / ablated.Intratumoural fat almost diagnostic (CT or chemical shift), 5% do not contain fatMay extend into renal vein and IVC
Tuberous sclerosis
AD, variable penetrance; >50% sporadicEpilepsy, mental retardation and adenoma sebaceumAlso subependymal nodules, giant cell astrocytoma, peripheral tubers, retinal hamartomas, cardiac rhabdomyomas, lymphangioleiomyomatosis, shagreen patches, subungual fibromas, bone cysts50% have renal lesionsBilateral renal cystsMultiple AMLs are sine qua non of TS (15% patients)RCC (1-2%)
Renal adenoma
Solid lesion
Renal Pelvis Tumours
Tend to maintain reniform outline of kidneyInverted Papilloma (No malignant potential, 20% risk of associated urothelial malignancy)TCCSCC (5% renal pelvis tumours,
TCC of Upper Renal Tract
Often multifocal; 40-80% have bladder TCC but only 3% bladder TCC later develop upper renal tract TCC10% of upper renal tract neoplasms, 2-4% bilateral, 2-7% calcificationHyperechoic on US and hyperattenuating on CTCauses faceless kidney - obliteration of sinus fat and infiltration of parenchymaStippling sign on IVP - tracking of contrast interstitially in papillary lesionStricturing - thus can mimic renal TB60% ipsilateral recurrence and 50% have lung metastasesStage I and II: limited to lamina propria / muscular layer, III: renal parenchyma / adjacent fat, IV: metastatic (usually liver, lung, bones)
Indications for partial nephrectomy
Solitary RCC
Von Hippel Lindau
AD, almost 100% penetranceUsually renal cysts25-40% develop clear cell RCC (often 30-40 y/o), often synchronous / metachronous; often screen from 20’s.Also have pancreatic cysts (30%), islet cell tumours, phaeochromocytomas (10%, often multiple and ectopic, 50-80% bilateral), retinal angiomas, ANS haemangioblastomasMore rarely endolymphatic sac tumours, cystadenomas of epididymis, broad ligament cysts