Renal Diseases Renal cysts and Tumors

CYSTIC DISEASES OF THE KIDNEYFluid filled spaces within the kidneyMay involve cortex or medulla or bothMay be unilateral or bilateralMay be unilocular or multilocularMay be congenital or acquiredMay be sporadic or genetically determinedClinical significance may be trivial or grave

CLASSIFICATIONS OF RENAL CYSTIC DISEASESPolycystic kidney diseases:1. Autosomal recessive (ARPKD) classic infantile polycystic disease with congenital hepatic fibrosis2. Autosomal dominant (ADPKD)Simple renal cystsAcquired renal cystic disease

Autosomal Recessive Polycystic Kidney Disease ( ARPKD )Rare, 1:6-14000 live birthsAbnormal gene located on chromosome 6p21May be still born or neonatal death due to pulmonary insufficiencyProgressive renal failureLow specific gravity, mild proteinuria, urine concentrating defect, anemia, hypertension CCFBilaterally symmetrical enlargement of kidneysSmooth surface with innumerable 1-2 mm cystsDiffuse fusiform dilatation of the collecting ducts

ARPKD ( Cont. )Enlarged but normally shaped pelvi-calyceal systemNormal reniform shape complete with fetal lobation & normal sized (undilated) ureterNormal glomeruli and tubulesNormal interstitium and no dysplasiaCongenital hepatic fibrosis is almost always presentNormal numbers of nephrons, no interstitial fibrosis and no dysplasia

Autosomal Dominant Polycystic Kidney Disease (ADPKD )World wide, 1:1000 in general populationAccounting for 6% of patients in dialysis and transplant programAbnormal gene on short arm of chromosome 16 i.e. 16p13.3(PKD-1). 4q12-22(PKD-2), 3rd locus found Present in 3rd-5th decadeDull loin pain, flank masses. azotemia, positive family history, hypertension, hematuria, colic etc.Prograssive renal failure anemia & GFR, Ur & Cr

ADPKD (CONT.)Associated cysts in liver of biliary type, in pancreas (10%), spleen,thyroid & seminal vesicleVascular anomalies including Berry aneurysms(33%), aortic aneurysm, aortic root dilatation and mitral valve prolapseDiverticular disease of the colon (80%)

ADPKD- Pathological FeaturesBilaterally enlarged kidneys (up to 4000 gms)Diffuse cystic (1-2% cystic nephrons) change with uninvolved intervening parenchymaVarying sized, numerous to innumerable generally spherical unilocular cysts, distributed in cortex and medulla obscuring normal reniform shape and corticomedullary junction, containing yellowish to turbid to brown to black colored fluidDistorted pelvi-calyceal systemCysts arising from any part of nephron or collecting duct

ADPKD- PATHOLOGICAL FEATURESCysts lined by single layer of cuboidal epitheliumNeoplastic change - uncommon

Simple Renal CystsExtremely common as age advancesIncompletely understood pathogenesisCommonly associated with scarred kidneysAsymptomatic with normal renal functionMay be solitary/multiple/unilateral/bilateralGenerally unilocular, round to oval of varying sizes

SIMPLE RENAL CYSTS (Cont.)Arises as dilated tubules or collecting ductsThin, translucent fibrous wall containing clear or amber colored serous fluid

ACQUIRED RENAL CYSTIC DISEASESecondary to end-stage renal disease as well as prolonged dialysis ( 9 months -7 yrs.)Kidneys are generally small but may be normal or even enlargedCommon in cortexSeems to be arising in either proximal or distal tubulesNeoplastic change are common

RENAL TUMOURSIn infants and children :Nephroblastoma ( Wilms tumour )In adults :Renal cell carcinomaRenal cell adenomaRenal oncocytoma

NEPHROBLASTOMA ( Wilms tumour )Embryonal tumour arising from nephrogenic blastemal cellscan differentiate in to several cell lines - blastemal, epithelial and stromalmany replicate developing kidneysCommon in young children / uncommon in neonates and infants90% in < 6yrs. old ( mean: 3yrs. in boys and 3.5yrs. in girls )

NEPHROBLASTOMAEtiology and PathogenesisGenerally unknownWorld wide i.e. No environmental factorsVariable incidence in racial groups : blacks> whites> OrientalsFamilial tendencies: 1% autosomal dominant with variable penetrance & expressivityGenetic predispositions WT-1 gene (11p13); WT-2 gene (11p15.5)

NEPHROBLASTOMAClinical FeaturesMost common genitourinary cancerAge: 1-3yrs., 98% in

NEPHROBLASTOMA Pathologic findings (gross)Usually solitary, sharply (well) defined masses with pseudocapsuleVariable size & weight (60-6350 gms. with a mean of 550 gms.)Uniform, pale gray to tan, divided by prominent fibrous septa in to lobulesMay be cystic, hemorrhagic or necroticNo specific location

NEPHROBLASTOMA Microscopic findingsGenerally triphasic pattern :blastemal, epithelial and stromal cell typemay contains heterologous elementsfavorable or unfavorable histology on the bases of nuclear anaplasia i.e. . . .marked nuclear enlargement (3x)abnormal mitoses i.e. . . . increased DNA

NEPHROBLASTOMA - SpreadLocalRegional i.e. . . lymphaticDistant :lungsliver

NEPHROBLASTOMAprognosis and treatmentDepends upon :stage, age and histologySurgery with chemotherapy for :stage I & II with favorable histologysurgery with chemotherapy and radiotherapy for higher stages and unfavorable histology

RENAL CELL CARCINOMAHypernephroma / Grawitzs tumour3% of all adult malignanciesworld wide, no racial predispositionsM:F = 1.6:1, 6th decade (mean 55 yrs)seems to be arising from mature renal tubulestobacco - smoked / chewed

RENAL CELL CARCINOMA ( Cont. )Chromosomal abnormalities :3p13 - clear or granular cell typetrisomy 17/ tri-or tetrasomy 7 - papillary typeRare familial associationAssociated with acquired cysts and / or in patients on chronic hemodialysis

RENAL CELL CARCINOMA Clinical Features & Diagnosisclassic triad :hematuria, flank pain and abdominal massmay be clinically occult, 30% presents with metastatic lesionPolycythemia due to erythropoietinconstitutional symptomsimaging techniques - useful

RENAL CELL CARCINOMAmode of disseminationDirect extensionVascular LymphaticLungs, lymph nodes, liver, bone brain, skin etc.

RENAL CELL CARCINOMA prognosisInfluenced by multiple factors :tumour sizeinfiltrative marginshistological typetumour stage - most importantCan be expressed in terms of histological types

RENAL CELL ADENOMAIncidental findings at autopsy (22%)Well demarcated, unencapsulatedPale yellow-gray, discrete cortical massUp to 2 cms. in maximum dimension