Calyceal diverticulum

Contributors: Cafer Zorkun M.D., PhD.

Synonyms and Related Keywords: Pyelocalyceal diverticulum

Overview
Calyceal diverticulum is a relatively uncommon cyst-like lesion, often discovered incidentally during ultrasound examination of the kidneys. Calyceal diverticulum is a urine-containing cavity within the renal parenchyma, communicating with the collecting system through a narrow channel.

Types

 * Two types are identified:
 * One is related to a minor calyx and usually located in the upper pole
 * Other is connected with the pelvis or a major calyx in the central portion of the kidney.
 * The majority of calyceal diverticulum are small and asymptomatic, and do not require any treatment.
 * Calyceal diverticulua may rarely cause urinary tract infection, renal colic, pyuria, hematuria or hypertension.
 * Mobile calculi and milk of calcium are characteristic findings in calyceal diverticulum.

Ultrasonography

 * Ultrasound examination suggests the diagnosis of calyceal diverticulum and it has a variable appearance.
 * The diverticulum may appear as a cyst-like lesion, indistinguishable from a simple cyst.
 * Recognition of mobile echogenic material within such a cyst-like structure is considered characteristic of milk of calcium. A cyst-like mass with milk of calcium is presumed to be a calyceal diverticulum.

Computed Tomography

 * CT has an important role in the presence of a complicated cystic mass diagnosed by ultrasound without the characteristic features of calyceal diverticulum.
 * The demonstration of the layering of contrast medium on delayed images is pathognomonic of these lesions.
 * The patency of the diverticulum is demonstrated by the gradual opacification on delayed images.

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