DDX of solid renal mass

Approach to the DDX of solid renal mass:

  • US is the first step in imaging
  • Be aware of congenital anomalies of renal formation
  • In the clinical setting of infection, strongly consider the diagnosis of acute pyelonephritis. If this diagnosis is made, repeat the US in a month to ensure the “mass” has resolved
  • In a neonate with a large mass, mesoblastic nephroma is most likely
  • If the mass has fat, consider angiomyolipoma
  • Otherwise you must move on to CT or MR and begin the workup for malignancy with a large mass, mesoblastic nephroma is most likely