second opinions are they necessary?

My sister is 31 and has discovered a lump in her brest, after going to the doctors they did an mamagram and the lump was noticable but not on an ultrasound.  The doctor told her to wait and see and now she has discovered 3 different lumps in the same breastwithin a 6 month period of time.  They are about the size of a marble and do not move with the skin.  Now I've heard that if they don't move with the skin it is usually cancerous is this true?  Also is there a difference between and ultrasound and a sonnagram?  What should her next step be?  Should she see someone other than her family doctor for a second opinion since they didn't dig further the first time?

[CCF-RN,MSN-rf]

Dear little:  Many cancerous lumps are "fixed."  That is, they don't move around under the fingertips of the examiner.  However, this is not universally true.  In most cases, it would be difficult, if not impossible, to tell if a "lump" were cancer by the way it feels.  An ultrasound and sonogram are the same thing.  Both tests use sound waves and are best at determining whether a lump is solid or fluid filled.  Your sister may want to seek an opinion from a physician who specializes in breast disease.  She is young to develop breast cancer and multiple lumps sound more like fibrocystic disease, but this is impossible to say without exploring her situation further.