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 I am a 49 female who is 5'10" and weighs 150 pounds. Three years ago, I had clear cell stage 1 - grade 3 kidney cancer in the right kidney. Had surgery all was good. This year we had a ultrasound instead of a Ct scan. The report came back 5 x 5 x 9 Mm benign-appearing echogenic focus in the mid to upper left kidney likely represents a small angiomyolipoma.
  Ok, the doctor said it is too small to biopsy. So we need to wait to see if it grows. Having a ct in November.
How often does it turn out to be benign? Should I be concerned? Is the only sure way to know if it is clear cell to biopsy? If it is this angiomyolipoma tumor, how often do you see this? it is hard to just wait. Is there something to do or not do, in terms of size? Thank you for your time.


It is not easy to make a diagnosis of angiomyolipoma from an ultrasound; it usually takes a CT scan.  I agree that a 5 x 5 x 9 mm mass is too small to biopsy and that doing a CT scan in 6 months or so is the right idea.  They can often make the diagnosis on the CT as the angiomyolipoma is mainly a lipoma meaning a fatty tumor which is far less dense than cancer.  This shows up well on a CT scan.  If so, a biopsy may not be needed.  Sticking a needle into a highly vascular tumor (that's the angio part!) may cause significant bleeding.

The concern is that with a history of a renal cell cancer, it would be reasonable to be highly suspicious of any new solid renal mass.  

All angiomyolipomas are benign.  You should be a little concerned but not worried.  A biopsy may not be needed or can be done at the same time as treatment if surgery or cryotherapy are done.  We usually like to do cyrotherapy for smaller tumors even if benign angiomyolipmas because they tend to enlarge and bleed.

By far, the most common solid tumors in kidneys are cancers, but angiomyolipomas (and oncocytomas which are also benign) do happen and we urologists see this from time to time.

While it's hard to wait, that's the best thing to do right now.  Your urologist's advice seems to be correct.  


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Stephen W. Leslie, MD


Questions concerning erectile dysfunction, kidney stones and prostate disorders including prostate cancer. I have a special interest in kidney stone disease prevention.


Full time practicing urologist with 30 years experience. Associate Professor of Surgery and Chief of Urology at Creighton University Medical Center. Editor in Chief of eMedicine Urology internet textbook. Author of only NIH approved book written for patients by a urologist on the subject of kidney stones "The Kidney Stones Handbook". Inventor of the "Parachute" and "Escape" kidney stone baskets and the "Calculus" stone prevention analysis computer program.

American Urological Association, Ohio State Medical Association, Sexual Medicine Society

Men's Health, Journal of Urology, Urology, Healthwatch Magazine, Emergency Medicine Monthly, eMedicine, "The Kidney Stones Handbook", and numerous articles in various newspapers. He is also the editor of the Urology Board Review by McGraw-Hill used by urologists to study for their Board Certification Examinations.

Graduate of New York Medical College with residencies completed at Metropolitan Hospital New York, Albany Medical Center and University of Wisconsin-Madison.

Awards and Honors
Thirlby Award of the American Urological Association. Rated as one the country's Best Urologists by the Independent Consumer's Research Institute

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