Deep lesions that are less than 1 cm in diameter are best aspirated under ultrasound or CT scan guidance. The skin is cleaned with an alcohol swab. The nodule is immobilized between the fingers, and the needle tip is rapidly directed through the skin into the nodule. Once the needle enters the mass, the needle is continuously aspirated while the needle is rapidly moved in and out to obtain the sample. Suction is then relieved, and the needle is withdrawn and detached from the syringe.
Air is aspirated and the material is expelled on glass slides.
The material is gently but rapidly smeared on the slides and immediately dipped in alcohol fixative. Some of the slides can be left to air dry for Diff-Quick staining and rapid evaluation. The fixed material is stained by Papanicolaou or hematoxylin-eosin stains, which are excellent for nuclear detail. The syringe is rinsed into a container with formalin for adequate fixation of cellblock material. Numerous studies indicate that needle tract contamination by malignant cells is a rare complication despite thousands of FNAs performed worldwide.