Renal sinus cysts are benign. They can be subdivided into 1. parapelvic cysts: originate from the adjacent parenchyma and protrude into the renal sinus 2. peripelvic cysts: originate within the sinus itself and have a lymphatic origin These are simple renal cysts that plunge into the renal sinus from the adjacent renal parenchyma. They are usually ...