A cystic mass that extends from the renal pelvis to outside the renal capsule is referred to as what?

The correct answer refers to a condition where a cystic mass is located in close proximity to the renal pelvis and extends beyond the renal capsule. This description aligns with the term "extrarenal pelvis," which indicates that the dilated renal pelvis structure is not contained within the kidney but instead extends outside its normal anatomical boundaries.

The extrarenal pelvis is characterized by a cystic appearance and can sometimes be mistaken for a renal cyst or hydronephrosis. However, it is fundamentally distinguished by this extension outside the kidney, which is crucial in distinguishing it from other conditions that may involve the renal area.

In contrast, a parapelvic cyst typically arises within the renal parenchyma or near the renal pelvis without extending past the renal capsule, making it a different entity. A renal artery aneurysm refers specifically to a vascular condition affecting the artery supplying the kidney, not a cystic mass. Grade 2 hydronephrosis describes a state of mild to moderate swelling of the kidney due to obstruction of urine flow, which does not involve the presence of an independent cystic mass extending beyond the renal capsule. Each of these alternatives has defining characteristics that separate them from the concept of an extrarenal pelvis.