Urogenital ImagingRenal dysgenesis
the result of disordered differentiation of
renal tissue. Dysgenic kidneys are often referred to as polycystic kidneys because cysts develop along malformed nephrons and collecting tubules, regardless of the underlying pathogenesis.
Type I, or infantile polycystic kidney (see polycystic kidney disease autosomal recessive ARPKD ), is a rare but fatal autosomal recessive condition characterized by multiple minute cysts in both kidneys and the biliary ducts of the liver.
Type II, kidneys occur bilaterally or unilaterally and vary considerably in size and shape. Microscopically, they are characterized by poorly developed glomeruli with collecting tubules that are lined with multiple cysts of varying size and are surrounded by undifferentiated mesenchyme. Like infants with unilateral renal agenesis, those with unilateral renal dysgenesis are usually asymptomatic at birth.
Type III, or adult type bilateral polycystic kidney (see polycystic kidney disease autosomal dominant ADPKD ), is an autosomal dominant condition characterized by intermingled normal and abnormal nephrons. Since some renal function is maintained, type III kidneys are not usually detected at birth.
Type IV, or hydronephrotic kidney, (see hydronephrosis), is thought to be due to obstructed urinary flow in the latter stages of development, most commonly from obstruction of the ureter or the lower urinary tract. With recent advances in sonography and surgery this otherwise fatal condition can be detected and treated surgically before birth. Ultrasound is the best modality for assessment of this condition, and if necessary CT can be performed.
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