Investigation of abnormal appearing thyroid glands on Tc-99m sestamibi breast scintimammography

Of 507 breast scintimammograms performed using Tc-99m sestamibi, 34 patients were incidentally found to have abnormal appearing thyroid glands. The authors sought to investigate the clinical significance and/or ascertain an extraneous causative factor for these findings. One cold thyroid nodule was detected and was proven benign through biopsy. Two cases of subacute and chronic thyroiditis were proven, and it is possible that additional patients had this disease process. Focal areas of increased thyroid Tc-99m sestamibi uptake were observed in eight patients and probably represent parathyroid adenomas, nonautonomous hyperfunctioning thyroid nodules, or nontoxic multinodular goiter. The results did not yield an extraneous causative factor, underlying pathology, or clinically significant disease in all of the patients investigated, but the findings suggest a need for careful evaluation of any unusual uptake in the thyroid gland and the rest of the image. The authors do not recommend investigation of all abnormal appearing thyroid glands on Tc-99m sestamibi scintimammography. However, clinical correlation should be recommended.