I have a 4mm questionable supraclinoid internal carotid aneurysm on the right. what is it and should i be extremely worried? i do have thyroid cancer and recently my oncologist after a nuclear scan saw a small nodule by a major artery. could this be?

First, I would have no clue as to the etiology of the "small nodule". Ask the radiologist to discuss potential causes. The carotid aneurysm may require further imaging to fully evaluate. Discuss with your doctor how next to proceed. Perhaps you could conference with the physicians accompanied by a family member or friend who could take notes.