Fatty compartment along the hilus of kidney that invests the renal calyces, pelvis, blood vessels, lymphatics and nerves (image A) & (image B).
Renal sinus abuts the renal cortical columns of Bertin without a connective tissue interface.
Important landmark for staging renal carcinoma (extrarenal extension).
Requirement for diagnosis of renal sinus invasion by renal carcinoma:
Tumor cells in direct contact with renal sinus stroma or fat cells.
Tumor within vessels that are clearly within the renal sinus fat.