Problems and pitfalls in thyroid cytology.

When performing fine-needle aspiration of the thyroid, the limitations of the technique must be considered and one must keep an open mind when examining the cytologic specimen. It is also important to develop a philosophy for handling the occasional difficult "gray zone" case. Some cases will be at the border of normal and abnormal and a philosophical approach concerning how to handle these problem cases is useful. One approach is to "play it safe" and classify as "suspicious" any lesion that clearly does not fit into a benign category. Sometimes, a discussion with clinicians about the degree of suspicion is appropriate, and minimally suspicious lesions might be followed up unless clinical indications point toward surgery. An intermediate to strong degree of cytologic suspicion usually mandates surgical exploration. Undoubtedly, we will continue to refine our diagnostic abilities in fine-needle aspiration cytology of the thyroid. The above discussion reflects the experience of one institution, represents the state of the art as of 1996 and may have to be revised in the near future.