title: Evidence of extraordinary growth in the progressive enlargement of renal cysts.
abstract: OBJECTIVE
  In autosomal dominant polycystic kidney disease, cysts derived from tubules are detected at birth by ultrasound (threshold for detection >7.0 mm); thus, fetal cyst growth rates must exceed 2300%/yr. In adults, the combined renal cyst component enlarges at approximately 12%/yr by growth of individual cysts. To explore this discrepancy, the growth rates of individual cysts were determined in adult polycystic kidneys.
  
  
  METHODS
  Diameter, volume, and growth rates of individual cysts were measured by magnetic resonance in 30 individual cysts in three adult patients over a span of 3 years. Results were confirmed in 22 cysts measured in five patients by computed tomography over a span of 11 years.
  
  
  RESULTS
  Mean cyst diameters were 20.4 +/- 9.9 mm (range 7.1 to 40.5 mm) at baseline and 25.8 +/- 15.6 mm (range 7.8 to 49.6 mm) after 3 years. Mean cyst volumes, determined by manual segmentation and summation of magnetic resonance cross sections, were 8.7 +/- 12.9 cm(3) (0.3 to 43.3 cm(3)) and 24.2 +/- 66.3 cm(3) (0.3 to 364.8 cm(3)) after 3 years. Mean cyst growth rates ranged from 6.9 to 23.9%/yr; the maximum growth rate was 71.1%/yr, far less than required to develop a 7-mm diameter cyst in utero. Results were similar in 22 cysts examined by computed tomography.
  
  
  CONCLUSIONS
  It was concluded that renal cysts detected by ultrasound in newborns must have grown at exuberant rates in utero; thereafter, expansion appears to proceed at much slower rates.
authors.affiliation: Kidney Institute, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA. jgrantha@kumc.edu
authors.forename: Jared J
authors.initials: JJ
authors.lastname: Grantham
authors.forename: Larry T
authors.initials: LT
authors.lastname: Cook
authors.forename: Louis H
authors.initials: LH
authors.lastname: Wetzel
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Cadnapaphornchai
authors.forename: Kyongtae T
authors.initials: KT
authors.lastname: Bae
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D018450:Disease Progression; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007668:Kidney / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D007690:Polycystic Kidney Diseases / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D055815:Young Adult