Calyceal diverticulum

Case contribution: Dr Radhiana Hassan


  • A 55 years old lady
  • Presented with right renal pain
  • US KUB done shows a small right renal cyst with wall calcification
  • For further assessment of the cyst
Ultrasound of right renal

Ultrasound findings:

  • There is cyst measuring 2.0 x 2.3 cm size in inter pole of right kidney.
  • There is hyperechoic foci measuring 1.2 cm size within the lesion that lies in the periphery and at dependant region
  • Posterior shadowing of the echogenic foci seen that could be calculus.
CT urography in axial planes

CT scan findings:

  • A round hypodense cystic lesion is seen at right upper pole measuring 1.7 x 2.1 x 2.1 cm (AP x W x CC).
  • The lesion has thin imperceptible wall and peripheral rim of wall calcification.
  • A small calculus is seen within measuring 0.9 cm.
  • On excretory phase the layering of contrast material is seen within likely due to communication with the upper pole major calyx.
  • No other lesion in both kidneys. No hydronephrosis.

Diagnosis: Calyceal diverticulum in the right kidney.


  • Calyceal diverticulum is outpouching from the renal calyx or renal pelvis into the renal cortex.
  • It is also known as pyelocalyceal diverticulum
  • It occurs equally in men and women.
  • There is no predilection for the left or right side.
  • The exact etiology is unknown but many favor congenital over acquired origin.
  • It is classified as type I, those communicating with a minor calyx or an infundibulum and type II in those emanating from the renal pelvis or major calyx.
  • Type I is the more common form calyx and is usually found in the upper pole
  • Type II are larger, tends to be symptomatic and are located in the interpolar region of the kidney.
  • Calyceal diverticulum is not seen on plain radiography.
  • If calcifications are present, these may be visible as with other renal calculi.
  • Ultrasound may reveal renal cyst but will not demonstrate its connection to the pelvicalyceal system.
  • Features of echogenic sediment, irregular morphology of wall and material inside may suggest a diagnosis of diverticulum.
  • On early phase CT scan, it appears as small round, low-attenuation areas adjacent to the calyces.
  • Following contrast administration, layering of contrast in the dependant position is noted. The patency of the diverticulum is demonstrated by the gradual opacification on delayed scans
  • A frequent complication associated with calyceal diverticulum is stones. Stone forms within the calyceal diverticula in up to 50% of cases.
  • Other complication include infection, hemorrhage or transitional cell carcinoma arising from its uroepithelial lining.
  • Management depends on symptoms
  • Conservative management in asymptomatic patients.
  • Intervention is considered if symptomatic.
Author: radhianahassan