ABSTRACT
A calyceal diverticulum is defined as a cystic cavity lined by transitional epithelium and connected to a minor calyx by a narrow channel. Most often they occur adjacent to an upper, or infrequently a lower pole calyx, and are categorized as type I. Infrequent type II diverticula are larger and communicate with the renal pelvis and tend to be more symptomatic.1 An incidence of 4-5 per 1000 excretory urograms has been reported in calyceal diverticular disease, with no apparent predilection for side, sex, or age.2 Its propensity to occur both in children and adults equally suggests a developmental etiology.3,4 The persistence of some of the ureteral branches of the third and fourth generation at the 5 mm stage of the embryo is believed to be instrumental in the formation of a calyceal diverticulum.5 An array of suggested acquired causes include among others the sequel of a localized cortical abscess draining into a calyx, infundibular stenosis, stone and infection mediated obstruction, and renal injury.
