Background: Thyroid nodular lesions are common clinical problems worldwide for which surgical intervention was the treatment of choice in many cases. Thus, it is challenging for the pathologist to distinguish the neoplastic nodule from non neoplastic ones and further, categorize the malignant tumors wherever possible.

Objective: The objective of this study was to cytological evaluation of FNAC based on  the Bethesda thyroid FNA classification system in evaluation of thyroid nodules as well as correlate relevant cases them histopathologically.

Materials and Methods: This study was conducted over 3 years. Fine needle aspiration was done by palpation or ultrasound guided, using a fine (25 G) needle, and cytological smears were stained by Giemsa, H&E and Papanicolaou stain. The cytological findings were classified according to the BSRTC.

Results: Of the 154 cases examined, benign lesions were the most common (92.1%), followed by atypia/follicular lesion of undetermined significance (4.5 %),malignant (3.9%), suspicious for follicular neoplasm/follicular neoplasm (3.9%), and suspicious for malignancy (3.1%). Good cyto-histological correlation (94.4%) was observed. Only 4.5% smears were non-diagnostic.

Conclusions:  FNAC is a simple, safe and cost-effective diagnostic modality in the investigation of thyroid disease with high specificity and accuracy. Accurately evaluated, it can reduce surgical intervention in many patients. However, histopathological diagnosis of thyroid nodules is still the gold standard for thyroid lesions.

Keywords: thyroid, cytology, cytopathology, TBSRTC, FNAC.

1. Edmund S. Cibas, MD, and Syed Z. Ali, MD. The Bethesda System for Reporting Thyroid        Am J Clin Pathol 2009;132:658-665
2. Zagorianakou P, Malamou-Mitsi V, Zagorianakou N, Stefanou D, Tsatsoulis A, Agnantis NJ, et al.The role of fine-needle aspiration biopsy in the management of patients with thyroid nodules. In Vivo 2005;19:605-9.  
3. Greenblatt DY, Woltman T, Harter J, Starling J, Mack E, Chen H, et al.Fine-needle aspiration optimizes surgical management in patients with thyroid cancer. Ann Surg Oncol 2006;13:859-63.
4. Krane JF, Nayar R, Renshaw AA. Atypia of undetermined significance/follicular lesion of undetermined significance. In: Ali SZ, Cibas ES, editors. The Bethesda System for Reporting Thyroid Cytopathology. New York: Springer; 2010. p. 37-50.
5. Das dk,khanna cm,triparthy etal. Solitary nodular goitre, revivew of cytolomorp-hologic features in 441 cases. Acta cytol 1999;43: 563 : 574.
6. Yang J, Schnadig V, Logrono R, Wasserman PG. Fine-needle aspiration of thyroid nodules: A study of 4703 patients with histologic and clinical correlations. Cancer 2007;111:306-15.
7. Fazeli R, VandenBussche CJ, Bishop JA, Ali SZ. Cytological diagnosis of follicular variant of papillary thyroid carcinoma before and after the Bethesda system for reporting thyroid cytopathology. Acta Cytol 2016;60:14-8
8. Jo VY, Stelow EB, Dustin SM, Hanley KZ. Malignancy risk for fine-needle aspiration of thyroid lesions according to the Bethesda system for reporting thyroid cytopathology. Am J Clin Pathol 2010;134:450-6.
9. Bongiovanni M, Spitale A, Faquin WC, Mazzucchelli L, Baloch ZW. The bethesda system for reporting thyroid cytopath-ology: A meta-analysis. Acta Cytol 2012;56:333-9.
10. Bongiovanni M, Cibas E, Faquin W. The role of thyroid fine needle aspiration cytology and the Bethesda system for reporting thyroid cytopathology. Diagn Histopathol 2011;17:95-105
11. Orell and Sterrett's Fine Needle Aspiration Cytology, 5th Ed, 2012;Churchill Livingstone

12. Hsu C, Boey j. Diagnostic pitfalls in the Fine needle aspiration of Thyroid nodules. A study of 555 cases in Chinese patients. Acta cytol 1987;31:699-704
13. Mittal N, Selhi P, Kaur H, Mittal A, Nagiraj A,Singh A, et al. Cytomorpho-logical analysis of categories in the Bethesda system and its accuracy in predicting thyroid neoplasms. Thyroid Res Pract 2018;15:84-8.
14. Mondal SK, Sinha S, Basak B, Roy DN, Sinha SK. The Bethesda system for reporting thyroid fine needle aspirates: A cytologic study with histologic follow-up. J  Cytol 2013; 30:94‑

Dr U.C. Dutta

Director, Lab & Blood Bank, Rahman Hospitals Pvt. Ltd. Guwahati, Assam

Former Prof.  & HOD, Deptt. Of Pathology, Gauhati Medical College, Guwahati, Assam