Differential diagnosis of perirenal cystic or non-cystic fluid collections. A review and case reports

A perirenal fluid collection, which is fluid located between the renal capsule and renal fasciae, is not a frequent diagnostic finding. When seen, either cystic, pseudo-cystic or non-cystic, several diagnostic possibilities must be kept in mind. The differential diagnosis of perirenal fluid, except for adrenal fluid, and the perirenal anatomy are described on the basis of three illustrative cases. Emphasis is on the radiological aspects.