Us of thyroid diffusely heterogeneous with multiple sub-centimeter nodules, 6mm isthmus, index nodules mixed echo-texture, what does this mean?

Check antibodies: Hi. That U/S is not specific, but Hashimoto's glands can look like that. Check TPO and thyroglobulin autoantibodies. If they're positive, it's Hashimoto's until proven otherwise. Why was the thyroid U/S ordered? Good luck!

Multinodular goiter: No undue risk of cancer. Should get blood tests to make sure not hypo or hyperthyroid. Recheck ultrasound in ~ 1 year to make sure no change in size of nodule(s).