Child with bilateral lumbar mass

These bilateral masses are since birth according to the parents and may have changed marginally in size according to them. What could be the cause of these b/l masses ?

 

Hint: It's a hernia

 

congenital bilateral lumbar hernias

 

Answer: Bilateral Lumbar Hernia

Discussion

It is one of the rare types of abdominal wall hernia.
The herniation is through inferior triangle of Petit. It is bounded below by the crest of ileum, laterally by external oblique and medially by latissimus dorsi.
It rarely gains entry into superior triangle of Petit which is bounded above by twelfth rib,medially by sacrospinalis and laterally by posterior border of external oblique.

 

Pop quiz. What's the ddx for a lower lumbar/flank mass that disappears when prone or supine?

 

Bilateral lumbar hernia

 

?

 

Renal mass