[Fine needle aspiration of the thyroid: the value of on-site evaluation].

Thyroid nodules are very common in the general population and most of them are benign. Fine needle aspiration (FNA) of the thyroid is routinely used because it is a rapid, simple, accurate and cost-effective technique which allows the adequate selection of patients who should be managed surgically. However, the diagnostic yield of FNA is variable and depends of multiple factors including the one who performs FNA, the aspiration and cytological slide preparation techniques, and cytopathologist's experience. On-site evaluation of thyroid FNA material and close clinico-pathological collaboration offer many advantages and optimizes the yield of FNA.