Fine-needle aspiration cytology of thyroid nodules: experience at the Queen Elizabeth Hospital, Barbados (1998-2002).

Fine-needle aspiration cytology (FNAC) of the thyroid nodule has become part of accepted practice defining the role of surgery. This study assessed a 5-year period comparing cytologic with histopathologic diagnosis in 256 samples from 234 patients (203 women and 31 men). Inadequate cytologic samples were obtained in 21.1% of cases. The sensitivity and positive predictive values for the detection by FNAC of thyroid neoplasms was 21.1% and 30.8%, respectively, with a specificity and negative predictive value of 79.5% and 70.0%, respectively. The overall FNAC accuracy was 61.9%. It is anticipated that improvement in diagnosis will develop from specific cytopathological training in thyroid FNAC, consideration of the cytopathologist performing the aspiration biopsy, and the development of immunohistochemical and molecular techniques applied to the cytologic smears. The principal inherent difficulty with thyroid FNAC is the inability to confidently distinguish hyperplastic follicular adenomas from microinvasive follicular carcinomas.