Fine needle aspiration: past, current practice and recent developments.

Fine needle aspiration (FNA) is a diagnostic technique that has become widely used. The procedure may be performed by interventional radiologists, endoscopists, pathologists and cytotechnologists; diagnostic interpretation of FNA samples is performed by pathologists and cytotechnologists. I provide here an introduction to the technique and applications of FNA with a review of current practice parameters and recent developments in the molecular application of FNA.