The thyroid nodule (previous post) is a "colloid nodule," apparently quite benign. Doctor L says take another look with ultrasound in six months or a year, see if it's growing. Otherwise it's fine if it isn't causing problems breathing or swallowing.
It's not. This drama is over.
I did actually increase my iodine intake a couple of months ago, so maybe the treatment, if any is needed, is already underway.