<prompt> FNAC is least diagnostic in which thyroid carcinoma-AnaplasticPapillaryFollicularThyroiditis  <response>: Ans. is c i.e., Follicular Ca o FNAC is the best investigation for the diagnosis of all thyroid carcinomas except follicular carcinoma. o It cannot differentiate bw follicular carcinoma and follicular adenoma. The definitive diagnosis of carcinoma is made when capsular and vascular invasion by the carcinoma is revealed. 