UG-FNA biopsy of the thyroid and CLNs is a safe and inexpensive
procedure that can be performed in the office. Complications such as hematoma and
severe pain are uncommon and the procedure provides a greater yield and is more
accurate than FNA by palpation. A baseline thyroid ultrasound is essential for
determining which nodules and/or CLNs require FNA biopsy and for selecting an entry
path. The needle path is either parallel or perpendicular to the ultrasound beam, where
the parallel path requires more practice but may be safer as it allows visualization of
the biopsy needle throughout the procedure. Negative pressure ‘aspiration’ or capillary
action biopsies are equally effective and a 25-27G needle is usually sufficient for solid
nodules, whereas a larger gauge needle may be required for the aspiration of cystic
content. The risk of a hematoma post-FNA biopsy is very low although it is important
to minimize the number of FNA passes, apply gentle compression at the biopsy site
after each pass, and to perform a brief ultrasound scan of the biopsy site at the end of
the procedure. It is unclear if holding anti-thrombotic agents before the procedure is
beneficial but it is important to ensure that in patients taking warfarin the international
normalized ratio (INR) is less than 2.5-3.0 before the procedure. In addition to
cytopathology, FNA biopsy allows measurement of tumour markers such as
thyroglobulin and calcitonin when clinically indicated. The Bethesda system and the
UK Royal College of Pathologists grading system are commonly used for reporting
thyroid cytopathology.
Keywords: Anti-thrombotic agent, Bethesda, Biopsy, Benign, Capillary FNA,
Calcitonin, Cytopathology, Fine needle aspiration, Hematoma, Lymph node,
Malignant, Parathyroid, Thyroid, Thyroglobulin, Ultrasound.
