Differential diagnosis of anomalies of renal formation

Approach to the differential diagnosis of anomalies of renal formation:

  • While performing renal ultrasound for the followup of findings on prenatal ultrasound or as part of the workup for urinary tract infection one should search for anomalies of renal formation:
    – Agenesis of the kidney evidenced by an empty renal fossa – but before this diagnosis can be made, abnormalities of renal ascent (ectopic kidney, horseshoe kidney, intrathoracic kidney) must be ruled out
    – Fetal lobulations of the kidney which disappear in a few weeks
    – Dromedary hump which is an abnormality in renal contour of the lateral left kidney which can mimic a renal mass
    – Tamm Horsfall proteins which manifest as echogenic renal pyramids which resolve by the end of the neonatal period
    – Duplication of the kidney along with ectopic ureterocele which can lead to vesicoureteral reflux