Which lesion is a benign fatty renal tumor that is often solitary and may be associated with tuberous sclerosis?

Which lesion is a benign fatty renal tumor that is often solitary and may be associated with tuberous sclerosis?

• A. Oncocytoma
• B. Lipoma
• C. Angiomyolipoma
• D. Adenoma

Answer: (C)

Angiomyolipoma is a benign renal tumor defined by a mix of blood vessels, smooth muscle, and fat. The fatty component is a clue that helps distinguish it from other renal masses, and the presence of fat is why this lesion stands out on imaging as a fat-containing kidney tumor. These tumors are often solitary, but they can be multiple, and a strong association exists with tuberous sclerosis, where renal angiomyolipomas are common hamartomatous lesions. The fat within the lesion and this syndromic link together make angiomyolipoma the best explanation for a benign fatty renal tumor that may be associated with tuberous sclerosis. Other renal masses like oncocytoma are solid and typically don’t contain macroscopic fat, and aren’t characteristically tied to tuberous sclerosis. A lipoma in the kidney would be fat-only but is much rarer and not the classic association with TS. Adenomas are usually adrenal and do not describe a fatty renal tumor.

Angiomyolipoma is a benign renal tumor defined by a mix of blood vessels, smooth muscle, and fat. The fatty component is a clue that helps distinguish it from other renal masses, and the presence of fat is why this lesion stands out on imaging as a fat-containing kidney tumor. These tumors are often solitary, but they can be multiple, and a strong association exists with tuberous sclerosis, where renal angiomyolipomas are common hamartomatous lesions. The fat within the lesion and this syndromic link together make angiomyolipoma the best explanation for a benign fatty renal tumor that may be associated with tuberous sclerosis.

Other renal masses like oncocytoma are solid and typically don’t contain macroscopic fat, and aren’t characteristically tied to tuberous sclerosis. A lipoma in the kidney would be fat-only but is much rarer and not the classic association with TS. Adenomas are usually adrenal and do not describe a fatty renal tumor.