Renal ectopia

Jump to navigation Jump to search
Renal ectopia
Renal scan image demonstrates cross-fused renal ectopia.
Image courtesy of RadsWiki
ICD-10 Q63.2
ICD-9 753.3

Renal ectopia Microchapters

Home

Patient Information

Overview

Historical Perspective

Classification

Pathophysiology

Causes

Differentiating Renal ectopia from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications and Prognosis

Diagnosis

Diagnostic Study of Choice

History and Symptoms

Physical Examination

Laboratory Findings

Electrocardiogram

X Ray

CT

MRI

Ultrasound

Other Imaging Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Surgery

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Renal ectopia On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Renal ectopia

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Renal ectopia

CDC on Renal ectopia

Renal ectopia in the news

Blogs on Renal ectopia

Directions to Hospitals Treating Renal ectopia

Risk calculators and risk factors for Renal ectopia

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: : Cafer Zorkun M.D., PhD.

Synonyms and keywords: Ectopic kidney

Overview

Renal ectopia describes a kidney that is not located in its usual position. It results from the kidney failing to ascend from its origin in the true pelvis or from a superiorly ascended kidney located in the thorax.

Pathophysiology

  • Normal ascent of the kidneys is required for formation of the extraperitoneal perirenal fascial planes.
  • Ectopia (or renal agenesis) results in failure of development of fascial layers in the flanks on the side not occupied by renal tissue.
  • Lack of restraining fascia leads to possible malposition of bowel into the extraperitoneal fat of the empty renal fossa and relaxation of mesenteric supports for bowel loops in this region.

Crossed-fused renal ectopia

  • Crossed ectopy = kidney located on the opposite side of the midline from its ureter. [1] [2] [3] [4]
  • In 90% of crossed ectopy, there is at least partial fusion of the kidneys (the remainder demonstrate two discrete kidneys on the same side, crossed-unfused ectopy)
  • Due to improper renal ascent in embryogenesis (4th-8th week of fetal life - normally, the kidney reaches its appropriate position at L2 level at the end of the 2nd month)
  • Fusion of the kidneys within the pelvis leads to crossed-fused renal ectopia.
  • Abnormally situated umbilical artery prevents normal cephalic migration. Another theory is that the ureteric bud crosses to the opposite side and induces nephron formation in the contralateral metanephric blastema.

Epidemiology and Demographics

  • Incidence: 1 out of 1,000 births.
  • 2:1 male to female ratio
  • A single renal mass with two collecting systems is located on one side of the abdomen.
  • Left-to-right ectopy three times more common.

Complications

Diagnosis

Imaging

  • Readily detected on conventional urography.
  • CT and US very useful.
  • On US, identified by characteristic anterior or posterior "notch" between the two fused kidneys.
  • Anterograde or retrograde ureterogram most often demonstrates normal bladder trigone without ureteral ectopy.
  • Blood supply usually anomalous.
  • Angiography recommended before surgical intervention.
  • Findings on CT or barium contrast studies of the bowel should be interpreted in light of bowel laxity in the region of the empty renal fossa (discussed above). In particular, distinction must be made from internal hernia.

CT Scan

Patient #1: CT images demonstrate a pelvic kidney

Images courtesy of RadsWiki


Patient #1: CT images demonstrate cross-fused renal ectopia

Images courtesy of RadsWiki

Patient #2: Renal scan images demonstrate cross-fused renal ectopia

Images courtesy of RadsWiki

References

  1. Dunnick, N.R., Sandler, C.M., Newhouse, J.H., and Amis, E.S. Textbook of uroradiology, 3rd Edition. Lippincott Williams and Wilkins, 2001.
  2. Dyer, R.B., Chen, M.Y., and Zagoria, R.J. Classic signs in uroradiology. Radiographics, 2004; 24:S247-S280.
  3. Gay, S.B., Armistead, J.P. Weber, M.E., and Williamson, B.R.J. Left infrarenal region: anatomic variants, pathologic conditions, and diagnostic pitfalls. Radiographics 1991; 11: 549-570.
  4. Meyers, M.A., Whalen, J.P., Evans, J.A. and Viamonte, M. Malposition and displacement of the bowel in renal agenesis and ectopia: new observations. AJR, 1972; 117,2: 323-333.

Template:WH Template:WS