A brief description of the Bethesda System for reporting thyroid fine needle aspirates.

Fine needle aspiration has become the most prominent, and the easiest way, to morphologically evaluate lesions of the thyroid. When done correctly, the sensitivity and specificity of thyroid aspirates for detecting malignancy is very high. Unfortunately, clinicians are sometimes confused by the terminology used in thyroid cytopathology reports. One way to mitigate confusion is for all pathologists to use the same diagnostic criteria and terminology. Standardized terminology for thyroid cytopathology reports has recently been proposed. The following article introduces the concept of the Bethesda System for reporting thyroid aspirates. Sample diagnoses are given to illustrate how thyroid cytopathology reports may appear using the Bethesda System.