Which of the following is NOT a sonographic finding associated with renal sinus lipomatosis?

Renal sinus lipomatosis is characterized by an abnormal accumulation of fat in the renal sinus region, which can have various sonographic manifestations. One of the distinguishing features of this condition is the appearance of the renal sinus, which typically shows increased echogenicity due to the excessive fat deposits, making it hyperechoic on ultrasound.

Increased echogenicity in the renal sinus is often accompanied by renal atrophy, where the actual kidney tissue decreases in size or volume due to the accumulation of fat and other structural changes. Decreased cortical thickness is also a finding that can accompany renal sinus lipomatosis, as the cortical substance of the kidney may diminish in response to the growth of fat in the sinus area.

Irregular renal contour is not a finding typically associated with renal sinus lipomatosis. This condition generally does not cause changes in the external contour of the kidney, which tends to remain smooth unless there are other underlying pathologies present, such as kidney stones or mass lesions that might distort the shape of the kidney. Therefore, among the answers provided, irregular renal contour is the feature that stands out as not typically related to renal sinus lipomatosis.