Multicystic dysplastic kidney is characteristically evidenced by multiple cysts replacing the entire kidney, without normal renal parenchyma. Echogenic dysplastic tissue may be present centrally.

Patients with unilateral MCDK must be examined thoroughly because up to one third of patients have additional genitourinary anomalies and up to 15% have extrarenal anomalies. In addition, the contralateral normal kidney must be monitored via ultrasound for adequate compensatory hypertrophy.