Hashimoto's thyroiditis: fine-needle aspirations of 50 asymptomatic cases.

The cytologic findings from 50 cases of asymptomatic Hashimoto's thyroiditis diagnosed by fine-needle aspiration are reviewed. All patients were referred for fine-needle aspiration by the same physician: 48 because of thyroid enlargement and the clinical suspicion of Hashimoto's thyroiditis, two because of a small thyroid nodule. Positive antimicrosomal (antithyroid peroxidase) and/or antithyroglobulin antibody titers (performed by the same laboratory using the same technique) were present in only 25 of 48 patients evaluated. Cytologic findings included a predominantly lymphocytic process in 92% of the cases and a predominantly oxyphilic (Askanazy/Hürthle) cell process in 8% of the cases. It is likely that all patients were in an early stage of the autoimmune process. Our data indicate that the incidence of Hashimoto's thyroiditis is considerably higher than when recognized only by serologic tests for antibodies.