I Have Recently Had A Pulmonary Embolism. A Scan 2

I have recently had a Pulmonary Embolism. A scan 2 days ago has revealed that it has since dissolved. as far as how I got the PE is a bit of a mystery as I do not have a blood disorder, no family related disease , haven't had a operation etc. Now that the clot has dissolved I have ceased taking the blood thinners (apixaban) and am scheduled this coming Monday to have my thyroid removed as I have a goiter. My question is, after a biopsy on my thyroid my specialist is saying the only way to completely rule out that I don't have cancer cells in my thyroid is to completely remove it. He is saying that there is no real explanation for the blood clot so this could mean cancer is present in my thyroid.Is this correct?