I too have hypothyroidism due to Hashimoto's & I also have a lump in my left breast. I just had a mammo & US yesterday & it was determined to be a lymph node as well. I have been diagnosed with hypo for a little over a year. My TSh was 289 at first & I have had a hard time getting it down. I am now on 125 mg of thyroxazine & have been for 2 months. I just had labs done on Friday & it is finally in the normal range...1.74. This blog has made me feel a tremendous amount of relief as I could not fathom why my node would be swollen in my breast. I am not nor have I been ill other than the hypo. I have been having a small amount of discharge from that breast but ni indication of infection. Thanks for all the comments!!!!!!