FINE NEEDLE ASPIRATION BIOPSY (FNAB)OF THYROID GLAND MASS : WHAT YOU NEED TO KNOW

Fine Needle Aspiration Biopsy(FNAB) is a minimally invasive procedure that can be performed on superficial (palpable) or deep organ, as thyroid gland, which is located superficially and palpable on the body,This procedure is relatively fast, cheap and can be performed in patient who is outpatient or hospitalizedand have a low risk complication. Thyroid gland FNAB has 93.4% sensitivity, malignancy positive predictive value of 98.6%, and 74.9% specificity.

            Thyroid gland is an organ which producing thyroid hormone that important for managing the body metabolism. The thyroid gland is located in the center and front aspect of the neck, and look like a butterfly, which is usually not palpable in normal condition. The imbalance production of thyroid hormone can be a low production (hypothyroid) or high production (hyperthyroid). The chief complaint ofthyroid gland  diseaseclinical manifestationcan be a mass or enlargement, beside the manifestation effect of thyroid hormone imbalance. But a mass with normal thyroid hormone production (euthyroid) can also present.

            FNAB on thyroid gland is usually performed if there is any solitary circumscribed mass or diffuse enlargement of thyroid gland, with symptom of hypothyroid, hyperthyroid, or in euthyroid condition. The mass will be move on swallowing, and this helpful in determining the site of the mass. On the other hand, ultrasonography (USG) is also helpful in giving the Radiologic imaging of the mass. There is no specific preparation for patient before performing this FNAB procedure, such as fasting. But USG is recommended to do before FNAB. There is no contraindication for FNAB.

The FNAB procedure is performed by a pathologist or sometimes a well trained clinician. By using small needle, the thyroid gland FNAB is done to have sample of thyroid cells. The needle is very thinner and shorter than needle for blood sample procedure or for medication injection. Usually 2 times puncture minimally are needed to get the FNAB sample. In some condition, the gland mass can be a cyst which is filled by cyst fluid. So the FNAB procedure is also aspirate the cyst fluid by the needle and syringe. The slides are made from material that is obtained by FNAB procedure, than evaluation under the microscope is performed by pathologist, to establish the diagnosis. This FNAB examination result will help the clinician to categorize the thyroid gland disease and its differential diagnosis, so the next patient management can be determined.

The result of FNAB examination from thyroid gland mass can be benign disease like inflammation, benign tumor or malignancy, which is need the next treatment from medication until surgery for thyroid gland removal to confirm the previous FNAB diagnosis. To be the underline, FNAB is not a procedure or examination to replace the tissue examination or histopathology from thyroid gland specimen that is obtained by surgery, but FNAB help to categorize the thyroid gland disease and its differential diagnosis, efficient investigation, time and resources saving.

The FNAB procedure and examination can be find in Anatomical Pathology laboratory in government or private hospitals, such as Sanglah Hospital in Denpasar Bali. Usually the patient come to Anatomical Pathology laboratory with clinician covering letter. The FNAB examination result is have to be delivered to the clinician who ask the FNAB, so the patient can get the next treatment or management.