Pediatric Radiology > Genitorinary > Hydronephrosis > Multicystic Dysplastic Kidney

Multicystic Dysplastic Kidney

Multicystic dysplastic kidney (MCDK) results from a severe ureteropelvic junction (UPJ) obstruction. The kidney is comprised of large, noncommunicating cysts. It is important to differentiate this from hydronephrosis. In hydronephrosis the cystic spaces are seen to communicate. In difficult cases renal scintigraphy can be useful. MCDK will show no excretory function. The kidney usually gets smaller over time. MCDK may be associated with other abnormalities in the contralateral kidney, most commonly UPJ obstruction.

Which of the following shows a multicystic dysplastic kidney? (The other is hydronephrosis.)
Remember that the multicystic dysplastic kidney has large, noncommunicating cysts whereas in hydronephrosis, the cystic spaces communicate.

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