A 60‐year‐old man has recently noticed a lump in the left side of his neck. On specific questioning he has not noticed any change in weight, shortness of breath or pain in the neck. His wife, however, feels his breathing is noisier than usual, and that his voice may have become a little rough. On examination there is a visible left‐sided thyroid mass with no associated palpable lymph node enlargement. Initial investigations from general practice show normal thyroid biochemistry.