[Abstract] Objective To investigate the clinical value of fine-needle aspiration (FNA) cytology examination of the thyroid gland. Methods Retrospective analysis of 474 consecutive cases of fine-needle aspiration of the thyroid gland performed in Cancer Hospital of Chinese Academy of Medical Sciences from October 2005 to January 2011. 218 cases (46.0%) of ultrasound-guided aspiration and 256 cases (54.0%) of palpation aspiration were performed. The cytological findings were classified into six grades: undiagnosable, benign, atypical cells, follicular-like tumor, suspicious malignancy and malignant. The preoperative cytologic diagnostic results of 157 of these surgical patients were compared with the postoperative histopathologic diagnostic results. Results Among the results of 157 surgically treated patients at all levels of thyroid FNA, the proportions of malignancy were: undiagnosable 2/7, benign 16.7% (9/54), atypical cells 3/9, follicular-like tumor 1/3, suspicious malignancy 83.3% (35/42), and malignant 97.6% (41/42). The sensitivity of thyroid fine needle aspiration to identify benign and malignant thyroid nodules was 85.4% and the specificity was 86.9%. The positive predictive value was 90.5%. Conclusion Fine needle aspiration cytology diagnosis of the thyroid gland can provide a more accurate preoperative diagnosis of thyroid disease. The six-level diagnostic method helps in the selection of clinical treatment plan. Zhang Bin, Department of Head and Neck Surgery, Cancer Hospital, Chinese Academy of Medical Sciences Fine-needle aspiration (FNA) is the most accurate and cost-effective diagnostic method for preoperative evaluation of the nature of thyroid nodules, and is listed as routine in all foreign guidelines [1]. However, in China, FNA is rarely performed and the diagnosis of thyroid nodules is unclear due to the old-fashioned physician’s concept, the limitation of the level of cytopathological diagnosis and the excessive concern of patients about thyroid nodules, which leads to serious overtreatment. The initial experience of head and neck surgery department of Cancer Hospital of Chinese Academy of Medical Sciences is reported as follows, hoping to draw the attention of colleagues. Data and methods I. Clinical data The clinical and pathological data of 474 consecutive patients who underwent thyroid fine needle aspiration from October 2005 to January 2011 were retrospectively analyzed in our hospital. Among them, 109 were male and 365 were female, male U female = 1U3.4; age ranged from 9 to 83 years, with a median age of 49.0 years. Puncture modality: thyroid puncture under palpation in 256 cases (54.0%, ultrasound-guided puncture in 218 cases (46.0%. II. Equipment Ultrasound-guided FNA was performed using a color Doppler ultrasound diagnostic instrument-prosound α10 with a high-frequency probe model UST-5412 (4-13 MHz 34 mm) on a fully digitalized pure acoustic beam imaging platform from Aloka, Japan. Syringes and needles were made of single-use plastic sterile 5 ml syringes and 22G needles (0.7 mm × 38 mm) from BD, USA. The liquid-based cytology examination cell fixative was ThinPrep® CytoLyt® solution, and the cell collection tube was a special collection centrifuge tube from Midsci, USA. Glass slides and 95%; alcohol solution were used for routine cell smears. Other supplies include sterile dressing change kit, sterile rubber gloves, 1% lidocaine, etc. Puncture method 1. Palpation puncture method: It is suitable for solid nodules that can be clearly palpated or have a diameter greater than 1.5 cm or cystic nodules with a solid component greater than 50% [1]. The puncture procedure is as follows: the patient is placed in a supine position with a pillow under the shoulder and the head on the healthy side. Local disinfection with 0.5% iodophor is performed without local anesthesia. The puncturer fixes the nodule with the left hand and punctures the nodule rapidly through the skin with the needle in the right hand. If the thyroid gland is not obviously enlarged, the angle between the puncture needle and the skin is about 45°; if it is obviously enlarged, the angle of needle entry can be enlarged. The depth of needle insertion is based on the operator’s feeling, and the needle tip is punctured to the central part of the swelling, and the assistant assists in pulling back the needle plug to create a negative pressure of about 3-4 ml. The puncturer will repeatedly aspirate the puncture needle in the nodule for 5 to 10 times and then pull out the puncture needle. The puncture site is taped with sterile excipients and the patient is instructed to press for 10 min. The operator pushes the puncture material in the syringe directly onto the slide, pushes the membrane, smears, and performs hematoxylin and eosin (HE) staining after rapid fixation in 95% alcohol. 2. Ultrasound-guided puncture method (Figure 1): the indications are as follows [1]: (i) the nodule is not palpable or less than 1 cm in diameter; (ii) a cystic nodule with a cystic component of >50%; (iii) the nodule is located on the back of the thyroid gland; (iv) the first puncture result is undiagnostic and requires re-puncture. The position is the same as for palpation puncture. First, ultrasound exploration of the thyroid gland is performed to clarify the nodule to be punctured, as well as the location and depth of the nodule. Local sterilization with 0.5% iodophor, sterile gloves, and 1% lidocaine are used for local anesthesia. The puncturer holds a sterilized ultrasound probe in the left hand and locates the nodule to be punctured. The needle in the right hand is rapidly punctured through the skin. The angle of needle entry is the same as for palpation puncture. The ultrasound-guided puncture needle is inserted into the central part of the nodule. The rest of the procedure is the same as for palpation puncture. After successful puncture, the puncture material in the syringe is washed directly into a vial containing approximately 25-30 ml of CytoLyt® solution (Cytyc, USA). The vial was placed in a shaker for 15 min and centrifuged at 600 r/min for 10 min (centrifugation radius 16 cm). The supernatant was discarded and the sediment was transferred to a vial containing 20 ml of PreservCyt solution and stored for 15 min. Thinprep2000® was produced, fixed in 95% alcohol, routinely stained with HE, and sealed with xylene clear resin [2]. 3. Determination of puncture results: according to the Bartholomew Society for Cytopathology on the diagnostic strategy of fine needle aspiration of the thyroid gland [3], cytological results were classified into six grades: undiagnostic, benign, atypical cells, follicular-like tumor, suspicious malignancy and malignant. The gold standard for determining the FNA results was the postoperative routine histopathological diagnostic results and the FNA results were compared with the histopathological results. 4. Statistical processing: SPSS13.0 software package was used for statistical processing. Multivariate logistic regression – partial maximum likelihood estimation forward method was used to analyze the variables that had a significant effect on the diagnosis of malignant nodules (P < 0.05). Results Of the 474 cases, 13.162/474) were undiagnosable, 50.8% (241/474) were benign, 7.2% (34/474) were atypical cells, 1.5% (7/474) were follicular-like tumors, 10.5% (50/474) were suspicious of malignancy, and 16.9% (80/474) were malignant. A total of 157 cases received surgical treatment, including 58 cases by ultrasound-guided puncture and 99 cases by palpation puncture. The sensitivity and specificity of the ultrasound-guided thyroid FNA diagnostic test were 87.5% and 85.0%, respectively, in the former case (10.3%) and 1 case (1.0%) in the latter case, and the sensitivity and specificity of the palpated thyroid FNA were 84.2% and 87.8%, respectively, with no statistically significant difference between the two by stratified chi-square test (P=0.975). The sensitivity and specificity of preoperative ultrasonography for determining the benignity and malignancy of thyroid nodules were 76.9% and 77.3%, respectively, while the sensitivity and specificity of thyroid FNA for determining the benignity and malignancy of thyroid nodules were 85.4% and 86.9%, respectively, with a diagnostic compliance rate of 86.0%; with a positive predictive value of 90.5 percent and negative predictive value was 80.3 percent (Table 2). There were 13 cases of missed diagnosis of thyroid FNA, including 5 cases of micro papillary carcinoma (tumor diameter ≤0.5 cm), 4 cases of papillary carcinoma, 2 cases of lymphoma, and 1 case each of follicular carcinoma and metastatic carcinoma. There were 8 cases of misdiagnosis: 6 cases of nodular goiter, 1 case of adenoma, and 1 case of Langerhans cell histiocytosis.