Expert: Claes-Gustaf Nordquist, M.D. - 1/31/2007

Question
Thanks for the great explanation but I have another question. Would having a cyst cause a strong echo therefore causing a shadow? But since the cyst is now gone and the shadowing persists, in your opinion, would this probably mean there is something else there causing the shadow? I hope my question makes sense. If you had a pt come into your practice with a hx similar to mine, would you be suspicious that there may be something else going on besides a simple cyst? Also, another question, if when I go back in a month and the shadow is still there but not as prominent, is it prudent to go ahead with the biopsy?
Thanks so much for your quick response and help.
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The text above is a follow-up to ...

-----Question-----
I am 42 yrs old and about 2-3 weeks ago, I developed left breast pain with redness and a large lump. I went to my surgeon who did an u/s that showed a cyst but also an area of shadowing . He was very concerned and sent me for a mammogram. I do not  have the official report of the mammogram but received a letter stating there was an area that needed further imaging.
I went back to my dr this week anticipating a biopsy of the suspicious area of shadowing. He did another u/s that showed the cyst was gone but the shadowing persists.He said it was possible the shadowing had something to do with the cyst and may resolve on it's own. He wants me to come back in a month and repeat the u/s . If the shadowing persists, he will then do a biopsy.
I had a fibroadenoma in the left breast 11 yrs ago with my pregnancy. This was removed.When I asked my dr if he was suspicious this could be a malignancy, he said he didn't know.
My question is what causes shadowing on an u/s and what is the significance of this? Is it reasonable to wait for a month to see if it is still there? On the u/s screen, it looked like an large upside down V.
Thank you for your help.
-----Answer-----
Ultrasound works like radar, only using sound waves instead of short radio waves. It sends in very high tones (too high for us to hear, that is why it is called ultrasound) with very high frequencies and consequently of very short wave lengths. These short waves will due to their shortness make it possible to make detailed pictures. The machine registers echoes from tissue structures that are in the way of these sound impulses going into a breast and by doing so builds up a picture of what is there. Behind a strong echoe you will automatically get a shadow since the sound is reflected back and there is no sound going further behind the reflecting structure. That is why it looks like an inverted V. If you think of something casting a shadow within a strong beam of light it looks just the same and for the same reason. Now a shadow can also be created by a sound absorbing structure/medium. If the sound is absorbed in something, you do not see it since no echoe is created but by its shadow you can still understand that it is there. I do not understand why you should have to wait! Your dr. is right in saying that we do not know what is there. The best way of finding that out is a biopsy! DEMAND ONE! Good luck!


Answer
You are welcome! Yes a cyst could cause an echoe (the cyst is a fluid filled space so there would be echoes from the interface between this fluid filled space and the surrounding tissues but none from the fluid filled inside of the cyst, making it "hypoechoic" = "little echoic") and there may be a shadowing on the further side of it (as seen from the machine). Yes there may be something there of importance. There may also be something there which is NOT important, but we do not know which so we should find out! Soonest! Yes I would (if I still worked, but I have retired). So I would arrange for a biopsy immediately! Why wait a month? Why not have it done ASAP?! Yes a biopsy SHOULD be done (anyway), but soonest! Do not wait! There may very well be nothing of importance there. But we do not KNOW that and it may be the oppposite! So why take chances! Have it done quickly, so you try to be on the safe side! Good luck! Thanks!