Fine-Needle Aspiration

Fine-needle aspiration, abbreviated FNA, is a diagnostic procedure used to investigate lumps or masses, in which a thin hollow needle of 23 to 25 gauge is inserted into the mass to sample cells that are then stained and examined under a microscope. The sampling and biopsy together are called fine-needle aspiration biopsy or fine-needle aspiration cytology, and the procedure is very safe and minimally invasive, often allowing a more invasive open or excisional biopsy to be avoided and eliminating the need for hospitalization. The first fine-needle aspiration biopsy in the United States was performed in 1981 at Maimonides Medical Center, and the modern procedure is widely used to diagnose cancer and inflammatory conditions.