Kidney nontumor / medical renal
Developmental & cystic diseases
Congenital anomalies-general
Author: Nikhil Sangle, M.D.
Last author update: 2 April 2012
Last staff update: 14 December 2023
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: Kidney (congenital abnormalities [title])
Table of Contents
Definition / general | Agenesis | Duplication of ureters | Ectopic (displaced) kidneys | Horseshoe kidney | Hypoplasia | Renal tubular dysgenesis | Diagrams / tables | Case reports | Gross images | Microscopic (histologic) imagesCite this page: Sangle N. Congenital anomalies-general. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/kidneycongenital.html. Accessed April 26th, 2024.
Definition / general
- 10% of individuals have urinary tract malformations, although many are asymptomatic
- 15% of congenital urogenital anomalies are secondary to an underlying chromosomal disorder
- In children, 20% of chronic renal failure is due to renal dysplasia or hypoplasia
- In adults, 10% of chronic renal failure is due to adult polycystic kidney disease
- Mass ultrasound screening detects congenital renal and urinary tract anomalies in 1% but not recommended since most would ultimately be detected via symptoms; most commonly vesicoureteral reflux, ureteropelvic junction obstruction, ectopic kidney, renal dysplasia (Pediatr Nephrol 2012;27:949)
Agenesis
- Complete absence of renal tissue; unilateral or bilateral; 0.03% of newborns but 0.3% of stillborn
- Bilateral agenesis: incompatible with life; associated with large adrenal glands; leads to Potter (oligohydramnios) sequence; possible causes include maternal insulin dependent diabetes mellitus and male sex of fetus but usually no specific etiology (PLoS One 2010;5:e12375)
- Unilateral agenesis: not fatal
Duplication of ureters
- < 1% of individuals
- Usually asymptomatic; may be associated with obstruction
Ectopic (displaced) kidneys
- Usually at pelvic brim, may have kinking of ureters (Urologia 2010;77:212, Clin Exp Nephrol 2009;13:531)
Horseshoe kidney
- Most common congenital kidney anomaly, 0.15 - 0.25% of all newborns
- 90% are fused at lower pole
- Associated with obstruction, anomalous superior vena cava (Circ J 2012;76:1253)
- Complete fusion of the kidneys produces a formless mass in the pelvis (pancake kidney)
Hypoplasia
- Rare; failure of kidney to develop to normal size without scarring
- Usually unilateral with a reduced number of nephrons and pyramids (6 or less) but otherwise normal architecture
- Associated with PAX2 mutations (J Am Soc Nephrol 2001;12:1769)
- Oligomeganephronia: type of hypoplasia with small kidney but hypertrophied nephrons due to compensatory hypertrophy caused by reduced number of nephrons
Renal tubular dysgenesis
- Rare congenital abnormality of renal development characterized by short and poorly developed proximal convoluted tubules without dysplasia or cystic disease (Hum Pathol 1986;17:1259)
- Characterized by oligohydramnios and the Potter sequence, pulmonary hypoplasia, calvarial bone hypoplasia with enlarged fontanels
- Causes: acquired (associated with renal hypoperfusion, Pediatr Dev Pathol 1999;2:25) or autosomal recessive (mutations in genes associated with angiotensinogen, renin, angiotensin converting enzyme or angiotensin II receptor type 1, J Am Soc Nephrol 2006;17:2253, Hum Mutat 2012;33:316)
- Identified in 1% of perinatal autopsies in 1991 (Hum Pathol 1991;22:147)
Diagrams / tables
Images hosted on other servers:
Renal hypoplasia
Case reports
- 36 week gestational age male with Klinefelter syndrome and bilateral renal agenesis (Arch Pathol Lab Med 2004;128:e44)
Gross images
Images hosted on other servers:
Agenesis - bilateral
Incomplete duplication
Horseshoe kidney
Microscopic (histologic) images
Images hosted on other servers:
Oligomeganephronic renal hypoplasia
