Fine needle aspiration cytology
Fine-needle aspiration cytology (FNAC) has been used as a tool to obtain specimens for the morphological diagnosis of numerous lesions in a variety of locations for more than 80 years.
Today, this diagnostic modality is more powerful than ever in making rapid preliminary diagnoses in neoplastic and nonneoplastic conditions, guiding further work-up of the patient or even allowing the initiation of definitive treatment. In many clinical situations, FNAC can render a definitive diagnosis either from aspiration smears alone using well-defined cytological criteria or from aspiration smears combined with clinical data, radiological findings, and the results of ancillary studies.
The main indication for FNAC are thyroid nodules. Thyroid nodules are a frequent finding in the general population, with palpable nodules found in 4–7% of adults.The vast majority (90–95%) of these nodules are benign. Fine-needle aspiration (FNA) of the thyroid has proven to be an integral and reliable method of evaluating patients presenting with a thyroid mass. Thyroid FNA acts as both a diagnostic test and a screening test.