Excessive accumulation of fat in the renal sinus is termed

• A. Renal sinus lipomatosis
• B. Renal parenchyma
• C. Renin
• D. Peripelvic cysts

Answer: (A)

Excessive fat in the renal sinus is called renal sinus lipomatosis. The renal sinus—the central area that contains the pelvis and calyces—becomes filled with adipose tissue, and the surrounding renal parenchyma often thins. On imaging, this appears as increased fat density or echogenicity in the hilum region, and the collecting system may seem relatively preserved or only mildly distorted, which helps distinguish it from true dilation due to obstruction. It’s a benign change that can be seen with aging or obesity and may accompany parenchymal atrophy. The other terms refer to different structures or processes: renal parenchyma is the functional kidney tissue, renin is an enzyme involved in blood pressure regulation, and peripelvic cysts are cystic lesions around the pelvis rather than fat accumulation in the sinus.