A 47-year-old woman went in for her first routine screening mammogram and was called back for a 13-millimeter lump she had never felt. The biopsy did not show breast cancer. It showed thyroid tissue, and later scans showed that the tissue was taking up iodine just like a normal thyroid gland.
A team that included radiologists at Cambridge University Hospital in the U.K. described the case in Radiology Case Reports, in a report posted online Sept. 1. Thyroid tissue in the wrong place is already rare. Thyroid tissue that settles inside the breast, the authors wrote, is "exceptionally uncommon, with only isolated case reports described in the literature."
