I would suggest that you get a 2nd and possible 3rd opinion just to see if all three doc's are on the same page. Being that your sis was diagnosed w/thyroid cancer, it is obviously hereditary, but does not mean that you also will get the same diagnosis. You must take precaution and be sure to have other opinions. Again...this is my opinion. Take Care.
How big are the nodules? If they are smaller than 2.0 cm, usually docs watch and wait. If it is smaller than 8.0 mm, then it gets tricky to do a biopsy.
Do you have any other hypo symptoms? My thyroid hormone did shrink my nodules.
Also, did you have a FT4, FT3 test to determine your frees? Are you terribly stressed and feeling anxious? If so, it could be attributed to leaky nodules making you hyper.
You should get the TGab and TPOab blood tests to determine if Hashimoto's is the cause of these nodules and high TSH.
Below is a website where I found my endo if you want a second opinion. Endos can biopsy nodules. Make sure you get an endo who tests and treats FT4 and FT3 levels.
http://www.thyroid-info.com/topdrs/
:) Tamra