Primary Echinococcal Cyst

A 28-year-old man was examined because of a mass in the right side of his neck. A thyroid scan with Tc-99m pertechnetate showed an area of decreased activity in the right lower lobe that corresponded to the palpable nodule. Because the fine-needle aspiration did not provide satisfactory specimens, the patient underwent surgery. The nodule was firmly attached to the right lobe and both were excised. A histologic analysis revealed that the cystic mass was consistent with an echinococcal cyst. Thyroid involvement by hydatid cysts, especially as a primary site, is very uncommon.