It's safe and wise to plan surgery and go for a biopsy of the lesion It's always good to go for a full fledged biopsy rather than just the FNAC , sometimes FNAC cannot give a fully detailed information about what the lesion is made up of The next reason for the surgery is sometimes such lump can put pressure on the windpipe which can lead to breathing issues Just to avoid any such risk better plan for the surgery

Good evening! As per reports USG shows changes and fnac is s/o colloid goiter If she is symptomatic better to go for excision biopsy by surgery

If ur mother having any symptoms like breathing difficulty, pain in neck , change of voice and cosmatically it is not looking good than their is need of surgery when all investigation r with in normal limit

As a precaution better to get surgery done