Welcome to HCM.
15 mms. fibroid
we call as seedling fibroid, and it being so small, you do not have to worry about it.
You have not mentioned, whether you are married, how many children you have.
Usually when one fibroid is seen, there is a possibility of other small fibroids also being present, but difficult to pick up, unless the sonography
is done by an experienced doctor with trans-vaginal approach.
Even if there are a few small fibroids, you do not have to worry. Just leave it alone, unless of course you are having heavy flow during menses, in which case you should consult a gynecologist.