Fine-needle aspiration diagnosis of primary hydatid disease of the thyroid; first reported case in the USA.

Echinococcosis or hydatid disease (HD) is a parasitic disease caused by species of the Echinococcus genus. Since the incidence of HD in the USA is very low and the primary HD of the thyroid is extremely rare even in endemic regions, the occurrence of primary thyroid HD is exceptional in the USA. Thyroid HD is rarely diagnosed by fine-needle aspiration (FNA). Our literature review revealed less than ten cases of primary HD of thyroid diagnosed by FNA worldwide. Hereby, we report the first case of a primary thyroid HD diagnosed by fine-needle aspiration in the USA.