Cystic cavity within the kidney, lined by non-secretory urothelium, communicating with a calyx or renal pelvis by a narrow isthmus. Calyceal diverticular do not have papillae and fill with urine passively.
Aetiology – thought to be persistence of ureteric bud branches which would normally degenerate.
Rare (< 1 %), and often asymptomatic, but up to 40 % of patients may develop stones.
Diagnosis of calyceal diverticulum:
- CT IVP – may appear as parenchymal or endophytic cyst on non contrast, but fills with contrast on delayed phase imaging
- USS – cystic appearance but may contain stone (shadowing) or milk of calcium
- RGP – connection with collecting system with narrow neck
- URS combined with II
Treatment of stones can be difficult:
