An ultrasound-guided cytological biopsy, also called fine needle aspiration cytology (FNAC) is, in many cases, the most precise diagnostic method for work-up of a tumor in the thyroid gland. WIth today's ultrasound equipment, the point of the needle can be placed within an area of about 2-3 mm.
For ultrasound guided FNAC of the thyroid gland, it is important that a cytologist or screener is present to immediately evaluate the quality of the material. This facilitates collection of a high number of representative samples. It also allows opportunities for collecting material for supplementary examinations.
In certain cases, it will be necessary to take a supplementary tissue sample for a histological biopsy to make a more definite diagnosis.
- Palpable tumor
- Solitary or dominant tumor ≥ 1 cm detected by ultrasound examination
- Diffuse and enlarged, rapid-growing tumor in the thyroid gland
For a tumor that is not palpable < 1 cm, FNA is indicated if:
- there is familial accumulation of the disease
- the patient has previously been irradiated to the neck
- there are detected suspect lymph nodes in the neck
- ultrasound finding gives suspicion of malignancy
- Diagnose a tumor in the thyroid gland