Not one benign nodule can not become malignant, either in the breast, thyroid or elsewhere in the body. A benign tumor will always be benign and can not become a malignant tumor (cancer). Both have cellular behaviors that differentiate them from the origin.
The benign nodules in the breast are the result of an exacerbated growth of its elemental structures, called ducts and stroma, with fibroadenoma being the most common benign breast nodule.
The relationship between a typically benign nodule and the risk of breast cancer is less than 0.2%, so the risk of a woman who has a benign lump in the breast developing this type of cancer is practically nil.
However, there are several types of benign breast nodules or tumors, and although the vast majority do not present a risk for breast cancer, regular medical follow-up is essential.
Already in thyroid, most of the nodules found in this gland are benign tumors called adenomas, therefore, with no chance of becoming malignant.
The nodules in the breast should be evaluated by a mastologist, while the endocrinologist is responsible for thyroid exams.
Learn more at:
What are the symptoms of a thyroid nodule?
Is thyroid nodule dangerous? What is the treatment?