Subacute thyroiditis: fine-needle aspiration cytology of 14 cases presenting with thyroid nodules

Subacute thyroiditis (SAT) is usually diagnosed clinically without the need for fine-needle aspiration. The cytologic literature on this condition is therefore rare. We report on 14 cases of SAT presenting with thyroid nodules. The majority of patients were women with a mean age of 46 yr. All had pain/tenderness in the thyroid area accompanied by fever or an elevated ESR. The salient cytologic features included cellular smears; multinucleated giant cells in 100% of cases, some ingesting colloid or neutrophils; fibrous fragments with enmeshed inflammatory cells were a constant feature; follicular cells were scant to absent in most cases. Granulomas were rare. Colloid, when present was thick, with central cracks and frayed edges. One case was suspicious for malignancy. We conclude that the cytologic features of SAT are predictable, particularly, in the appropriate clinical setting. FNA is also helpful in ruling out concomitant neoplastic conditions.