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Monday, March 2, 2015
Is it cancer if the kidney is enlarged or could it be something else?
There are several causes of kidney enlargement, and some of them can be distinguished from each other by either CT scan or ultrasound:
1. Obstruction or blockage to urine flow (ultrasound will show a large kidney with a collection of urine in the middle).
2. Diabetes: often enlargement occurs as an early sign of diabetic kidney disease (but does not necessarily mean that a person will actually develop kidney disease).
3. HIV infection: here the enlarged kidneys also appear white on ultrasound (instead of their normal dark-gray color). Renal failure occurs in association with kidney enlargement in AIDS.
4. Some types of cancer: such as leukemia or lymphoma, in which the cancerous cells can spread throughout the kidney, causing it to appear enlarged; or kidney cancer (or metastatic cancer, for instance from the lung), in which case the actual tumor can be seen as a mass that can be distinguished from the normal part of the kidney.
5. Amyloidosis: here a protein called amyloid is deposited in various organs such as the skin, heart, liver, and/or kidneys. Like HIV infection, it may give the kidneys a white appearance on ultrasound.
6. Polycystic kidney disease: here the kidneys are replaced by cysts (fluid-filled round sacs) that gradually replace the kidney and make it look like a bunch of grapes. The ultrasound appearance is quite characteristic, as the individual cysts can be clearly seen.
So, as you can see, there are multiple causes of renal enlargement. Most of the time when the kidneys are enlarged, it is not due to cancer.
Mildred Lam, MD
Associate Professor of Medicine
School of Medicine
Case Western Reserve University