For thyroid gland is boarderline enlarged. right has single nodule likely adenoma. what does this mean?

Probably benign : Many thyroid glands are enlarged, and borderline means just slightly above normal size. The only way to tell if a thyroid nodule is benign or cancerous is with a biopsy. While some other tests may suggest it is benign the biopsy is the best way to tell.

It depends: Thyroid nodules are common in the population, especially in women. Most thyroid nodules are benign. Nodules over 1 centimeter in size are typically biopsied to be more certain that they are benign. One cannot be certain about the nature of a nodule just by its appearance on ultrasound. It is also important to check thyroid function tests to make sure that they are normal.