Fine-needle aspiration

Fine-needle aspiration
Medical diagnostics
Micrograph of a needle aspiration biopsy specimen of a salivary gland showing adenoid cystic carcinoma. Pap stain.
MeSH	D044963
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Fine-needle aspiration (FNA), or fine-needle aspiration cytology (FNAC), is a diagnostic procedure used to investigate lumps or masses. In this technique, a thin (23-25 gauge), hollow needle is inserted into the mass for sampling of cells that, after being stained, will be examined under a microscope. There could be cytology exam of aspirate (cell specimen evaluation, FNAC) or histological (biopsy – tissue specimen evaluation but only if it is done as a biopsy rather than aspiration ). Fine-needle aspiration biopsies are very safe, minor surgical procedures. Often, a major surgical (excisional or open) biopsy can be avoided by performing a needle aspiration biopsy instead. In 1981, the first fine-needle aspiration biopsy in the United States was done at Maimonides Medical Center, eliminating the need for surgery and hospitalization. Today, this procedure is widely used in the diagnosis of cancer and inflammatory conditions.

A needle aspiration biopsy is safer and less traumatic than an open surgical biopsy, and significant complications are usually rare, depending on the body site. Common complications include bruising and soreness. There is a risk, because the biopsy is very small (only a few cells), that the problematic cells will be missed, resulting in a false negative result. There is also a risk that the cells taken will not enable a definitive diagnosis.

This type of sampling is performed for one of two reasons:

When the lump can be felt, the biopsy is usually performed by a cytopathologist or a surgeon. In this case, the procedure is usually short and simple. Otherwise, it may be performed by an interventional radiologist, a doctor with training in performing such biopsies under x-ray or ultrasound guidance. In this case, the procedure may require more extensive preparation and take more time to perform.

Also, fine-needle aspiration is the main method used for chorionic villus sampling, as well as for many types of body fluid sampling.