Cong Renal Abnormalities-MH

Congenital RenalAnomalies in Adults

Mindy M. Horrow, MD, FACR

Director of Body Imaging

Albert Einstein Medical Center

Outline

•Abnormal Kidney

•Location

•Fusion

•Duplication

•Other

Ureteropelvic JunctionObstruction

Chronic R UPJ Obstruction

Compensatory Hypertrophy L Kidney

Acute left flank pain

Acutely obstructing L UPJ

Right Kidney

Left Renal Fossa

Multicystic dysplastic leftkidney

Multicystic Dysplastic Kidney

•Several Forms

–Classic- random configuration of cysts

–Hydronephrotic form- discernable dilated renalpelvis surrounded by cystic structures

–Solid Cystic Dysplasia- smaller cysts with greateramount nonfunctional parenchyma

•Competing Theories

–Ureteral obstruction in utero

–Abnormal induction of metanephric blastema byureteric bud.

–(In both MCDK and UPJO, left kidney more ofteninvolved than right)

Multicystic Dysplastic Kidney

•Bilateral MCDK incompatible with life

•50% with other urinary tract anomalies: UPJO, refluxin contralateral kidney (15 – 20%)

•Affected kidney involutes or decreases in size in 60-70%, which can take up to 20 years or occur beforebirth.

•Rarely become symptomatic

Right Multicystic Dysplastic Kidney

Duplicated Right Collecting System

Bifid Left Collecting System

Right ureters join before bladder =Incomplete Duplication

Duplication of Ureters = RenalDuplication

•Most common anomaly of urinary tract

•Incomplete duplication three times morecommon than complete, which is reportedto occur 1/500

•May be discovered in utero, in childhoodor less frequently in adulthood or autopsy

•Duplication is a common cause of anenlarged kidney

Incomplete Duplication

•Embryology not well understood but mayoccur when single ureteral bud branchesbefore reaching metanephric blastema.

•Duplicated ureters unite at variable distancefrom kidney with only one ureteral orifice

•Ureteroureteral reflux is common buttransitory.

Acute Left Flank Pain

Complete left ureteralduplication with calculusin ureterocele

Complete Duplication and theWeigert-Meyer Rule

•Ureters arise from Wolffian ducts.

•Ureter of lower pole arises inferiorly and isincorporated into developing bladder first,inserting superiorly and laterally to ureter ofupper pole

•Ureter of upper pole remains with wolffianduct longer, inserting more inferiorly intobladder or wherever remnants or derivativesof wolffian duct are found.

Complete Duplication

•Ureters arising from normal position onWolffian duct have normally positionedureteral orifices and normal upper tracts.

•Upper pole usually consists of only a fewcalices or compound caliceal group drainedby single infundibulum, while lower pole hasmost of the calyces.

Ectopic Ureterocele

•Dilatation of intravesical component of upper poleureter (ureterocele) is usually associated withdilatation of ureter and calyces

•Occurs 8 times more frequently in women

•Appears on US as thin walled “bleb” or “cyst” inbladder base at ureteral orifice

•Often associated with an obstructed dysplastic upperpole moiety

•Ipsilateral ureter, pelvis and calyces may be normalor extremely small.

R Sag lateral

R Sag medial

Trv superior pole

Trv mid pole

Duplicated Collecting SystemRight Kidney

Chronic obstruction upper pole

moiety, with ectopic ureterinserting into prostatic urethra

Duplicated right collectingsystem with chronic uppermoiety obstruction, insertioninto prostatic urethra,secondarily infected

Acute right flank pain

Duplication

•Appearance of upper tract predicts site of insertion:normal pelvicaliceal system relates to normallypositioned ureteral orifice. Extremely ectopic ureteralorifice relates to dysplastic, poorly function moiety.

•Most common complications: reflux, ectopicureterocele, ectopic ureteral insertion, UPJ lowermoiety (more in males).

•REFLUX: into lower pole because superior lateralposition results in short intramural segment whichpredisposes to reflux.

•OBSTRUCTION: of upper pole, typically withureterocele and/or ectopic insertion

Fernbach. Radiographics 1997;17:109

Ectopic Ureteral Insertion

•Since upper pole stays with Wolffian duct longer,ureter may insert into Wolffian duct remnant ratherthan bladder

•Males: seminal vesicle, vas deferens, ejaculatoryduct, prostatic urethra

–Extravesical insertions are suprasphincteric producinginfection, inflammation, mass such as epididymitis,orchitis.No enuresis

•Females: vagina, urethra, urethrovaginal septum,Gartner ducts

–Ectopic insertion is beyond spincter, symptoms of dribblingor primary incontinence

Duplicated rightcollecting systemwith Muellerian cyst

Right Kidney

SUP

MID

INF

Duplicated right Collecting System

Left Column of Bertin

Horseshoe Kidney

Normal Adrenal Glands

Fusion Anomalies: Horseshoe

•Fusion at one pole, 90% lower pole.

•Abnormal fusion probably occurs at 5 – 12 mmembryo stage, when kidneys fuse in pelvis beforerenal capsule has matured.

•Ascent of fused kidney is hindered by IMA

•Most common fusion anomaly, 1/400

•Complications: UPJ obstruction, recurrent infectionsand calculi due to stasis, increased risk of trauma,tumors (Wilm’s tumor, carcinoid, transitional cell CA)

•Other associations: urogenital, GI, neurologic,skeletal, chromosomal (XO, Trisomy 18)

Horseshoe Kidney

•Fusion site or isthmus usually composed ofrenal parenchymal tissue, but can be fibrous

•Isthmus is anterior to aorta and IVC, posteriorto IMA

•Renal pelves are malrotated and lie anteriorly

•Blood vessel variations are common

•Most patients are asymptomatic or presentwith urinary tract infections

Horseshoe Kidney with non-obstructing left sided calculus

Horseshoe Kidney with dilatedextra renal pelvis/ mild UPJO

Pancake Kidney just above uterus

Pancake Kidney, linear adrenal glands

Right Iliac Kidney

BilateralDuplications

Left renal fossa

24 year old with right pelvic mass

Right Pelvic Kidney

Left Kidney duplicated and malrotated

Crossed Renal Ectopia

Bicornuate Uterus

Right Renal Fossa

Empty Left Renal Fossa

Crossed Fused Ectopia

Right Renal Agenesis

Bicornuate Uterus

36 year old male

Left renal agenesis

Ipsilateral seminalvesicle cyst

Anomalies of the SeminalVesicles

•Cysts: isolated, associated with upper tract anomaliesor autosomal dominant polycystic kidney disease

•Usually become apparent in 2nd or 3rd decades withsymptoms of hematuria, hemospermia, epididimytis,prostatitis, infertility, UTIs

•Associated with ipsilateral renal agenesis or dysplasiain 2/3 of patients, reflecting maldevelopment of distalmesonephric duct and faulty ureteral budding withatresia of ejaculatory duct leading to obstruction andcystic dilatation of seminal vesicle

•Differential Dx: true prostate cysts, mullerian ductcysts, prostatic utricle cysts, hydronephrotic pelvickidney, bladder diverticula, ureteroceles

Arora. AJR 2007;189:130

31 year old with microscopic hematuria

No right kidney visualized

Crossed Fused Ectopia

Versus

Duplicated collectingsystem and absent rightkidney

Need information about ureters to make distinction

Right Kidney

Left Kidney

Megacalyces

Megacalyces

•Congenital underdevelopment of papillae leading toincreased number and size of calyces

•Calyces have a faceted or polygonal shape with nofornices or papillary impressions and with hypoplasticmedullary pyramids

•Hypothesis for pathogenesis is anomalous ureteralbud division leading to extra calyces at the expenseof the medullary portion of the kidney

•Diagnosis should be made only in patients withoutprior or concurrent obstruction or reflux.

•Renal function is normal, kidney is large

Megacalyces

Non-obstructing right calculi

Left sinus lipomatosis

Megaureters

Megaureters

•Enlarged ureter with or without dilatation of uppercollecting system.

•Primary

–Obstructed Primary Ureter: Dilatation above a short(0.5 – 4 cm) aperistaltic, normal caliber ureter withnormal insertion into bladder. Similar to achalasi andHirschprung disease. Cause unknown.

–Refluxing Primary Ureter

–Nonrefluxing unobstructed primary megaureter

•Secondary

–Result of some abnormality such as urethral valves,neurpathic bladder, urethral structure, etc.