Diagnostic Ultrasound - Abdomen and Pelvis

Renal Ectopia
Diagnoses: Urinary Tract
○ Arrested migration during embryologic development
○ RE inherited as autosomal recessive trait; reported in
monozygotic twins
○ CFE related to abnormal development of ureteric bud
and metanephric blastema during 4th-8th weeks of
development
• Associated abnormalities
○ Other genitourinary abnormalities in ~ 1/2 of cases
– RE
□ Vesicoureteral reflux (most common associated
abnormality)
□ Contralateral renal abnormalities in up to 50% of
RE such as renal agenesis
□ Absent or hypoplastic vagina
– CFE
□ Megaureter, cryptorchidism, urethral valves,
multicystic dysplasia
○ Occur in conjunction with anomalies in other organs in ~
1/3 of cases
– Skeletal (up to 50%)
□ Rib and vertebral anomalies; scoliosis may impact
renal ascent
□ Absence of radius
– Cardiovascular (40%)
– Gastrointestinal (33%)
□ Anorectal malformations such as imperforate anus
– Ears, lips, palate (33%)
□ Low-set or absent ears
□ External canal atresia
□ Cleft palate
DIAGNOSTIC CHECKLIST
Image Interpretation Pearls
• Do not confuse RE with mass in pelvis or thorax
• Do not confuse CFE with renal mass
SELECTED REFERENCES
1. Solanki S et al: Crossed fused renal ectopia: challenges in diagnosis and
management. J Indian Assoc Pediatr Surg. 18(1):7-10, 2013
2. Chang PL et al: Prenatal diagnosis of cross-fused renal ectopia: does color
Doppler and 3-dimensional sonography help? J Ultrasound Med. 30(4):578-
80, 2011
3. Siegel MJ, ed. Pediatric Sonography. 4th edition. Baltimore: Lippincott
Williams & Wilkins, 2011
4. Singer A et al: Spectrum of congenital renal anomalies presenting in
adulthood. Clin Imaging. 32(3):183-91, 2008
5. Guarino N et al: The incidence of associated urological abnormalities in
children with renal ectopia. J Urol. 172(4 Pt 2):1757-9; discussion 1759, 2004
6. Goodman JD et al: Crossed fused renal ectopia: sonographic diagnosis. Urol
Radiol. 8(1):13-6, 1986
7. McCarthy S et al: Ultrasonography in crossed renal ectopia. J Ultrasound
Med. 3(3):107-12, 1984
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CLINICAL ISSUES
Presentation
• Most common signs/symptoms
○ Commonly asymptomatic, incidental finding
○ May present with signs and symptoms of obstruction,
urolithiasis, reflux, and infection
Demographics
• Epidemiology
○ RE: Pelvic ectopia, most common
– Noted in 1:500 to 1:1,200
○ CFE represents 2nd most common fusion abnormality
after horseshoe kidney
– Male predominance, with incidence reported as M:F =
3:2
– Incidence reported ranging from 1:1,000 to 1:7,500
on autopsy studies
○ Crossed nonfused RE: Very rare, reported as 1:75,000
Natural History & Prognosis
• Complications
○ ~ 50% have complications related to vesicoureteral
reflux, hydronephrosis, stones, and infection
– Repeated infections can lead to scarring
○ May have increased susceptibility to trauma
○ Increased incidence of multicystic dysplasia
Treatment
• Treat complications
• No need to separate fused components