What is a characteristic sonographic finding in cases of renal lipomatosis?

In cases of renal lipomatosis, a characteristic finding on ultrasound is the presence of a hyperechoic renal sinus. This occurs due to an accumulation of fat within the renal sinus area, which appears bright on ultrasound, distinguishing it from other renal conditions.

This increased echogenicity in the renal sinus is indicative of the fat deposits that characterize renal lipomatosis. While renal atrophy and irregular renal contour might be identified in other conditions affecting the kidneys, they are not specific to renal lipomatosis. The hyperechoic renal cortex is not typical in renal lipomatosis, as the cortex itself usually would not appear hyperechoic in the presence of this condition. Thus, the standout feature that associates with renal lipomatosis is the hyperechoic renal sinus, which helps to recognize this condition during a sonographic examination.