They've already said that your nodules are benign (not cancer), so there's really not a lot to worry about. I can't see any reason they'd have to remove your thyroid since the nodules are benign and you're not hyper.
The whole thyroid issue - how the thyroid works, etc can be a bit overwhelming when you're first learning about it, but since you've been on medication for 20 yrs, staying on it will be no big deal. You just have to get the right dosage.
So - I'll explain just a little bit about Hashimoto's and Graves Disease. Both are autoimmune conditions that not curable and eventually destroy the thyroid. As I noted, Graves Disease is always associated with hyperthyroidism (too much thyroid hormones) and Hashimoto's is most often associated with hypothyroidism (not enough hormones), though Hashimoto's can sometimes be associated with hyper in early stages. Hashimoto's is the most common cause of hypothyroidism in the developed world, though there can be other causes.
Since you've been on thyroid medication for so long, I'm surprised your doctor has never tested for Hashimoto's, as it's very simple blood tests. The thing is that some doctors just "assume" Hashimoto's and don't bother to test for it. Anyway the tests you need are Thyroid Peroxidase Antibodies (TPOab) and Thyroglobulin Antibodies (TgAb). You need them both because they're both indicators for Hashimoto's and without them, you could be misdiagnosed.
Hypothyroidism caused by Hashimoto's isn't treated any different from any other type of hypothyroidism - replacement hormones are prescribed to keep up with the destruction of the thyroid gland. Hashimoto's causes certain characteristics of the thyroid gland, which IMO, is what they're seeing with your ultrasounds. It's possible for Hashimoto's to "flare" once in a while, causing medications to appear not to work and/or causing hormone levels to be off. It can also cause goiter (swollen thyroid) and enlarged nodules.
Adequate replacement medication can often be conducive to shrinking the goiter and/or nodules. Hopefully, the endo will be willing to provide an adequate dosage.
Please don't hesitate to ask any questions you might have. I'd rather answer questions than have you feel worries/overwhelmed.
As Jasper1966 stated, thyroid nodules are very common with hypothyroidism and/or Hashimoto's. Approximately 95% of nodules are benign. Do you know how large your nodules are? If they're less than 2.0 cm, it's unlikely they would do a FNA unless the nodules indicate strong possibility of cancer. You've already say they're "non-cancer" aka benign, so they won't do FNA.
I have a solid nodule on my thyroid that's been determined (via ultrasound) to be "moderately suspicious" for cancer but it was < 1.0 cm so they didn't do FNA. Because thyroid cancer rarely spreads to other parts of the body, it's safe to watch my nodule for a year to see what it does. It's been there for years, but this is the first time there's ever been a worry about cancer. The ultrasound that determined it to be moderately suspicious was done in September 2020, so we'll do another in a few months and see if it's changed. I have noticed that I seem to have a lot phlegm in my throat and have to keep clearing it a lot.
Some noduleds can be shrunk with the use of thyroid hormones. Could you please post the reference ranges for your FT4 and FT3? Ranges vary lab to lab and have to come from your own report. Your levels seem very low, based on what we normally see, but again, that depends on the reference ranges used by your lab... It looks like you could definitely use an increase in thyroid medication.
Thyroid nodules are very common and tend to be rather benign. Once they are detected then the next step is the biopsy using fine needle aspiration. Try to stay positive and remind yourself that the overwhelming percentages are in your favor. They can try to shrink it with medication, observe and monitor over time, etc. It is a nuisance but not debilitating. Best of luck to all of you.
Hi. I don't have an answer for you. However, I am 51 and have also been on thyroid meds for more than 20 years and am just about to undergo investigations for multiple probably thyroid nodules.... 1st ultrasound tomorrow.... so I would like to follow your discussion here.