THE BETHESDA SYSTEM FOR REPORTING THYROID FINE NEEDLE ASPIRATES

* Sharma A 1 , Shinde R.M 2 , Deshpande T 1 and Raghuwanshi P 1 . 1. Post Graduate student, Department of Pathology, D.Y. Patil Medical College, Kolhapur. 2. Associate Professor, Department of Pathology, D.Y. Patil Medical College, Kolhapur. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

The Bethesda system for reporting thyroid cytopathology represents a major step towards standardization, reproducibility, improved clinical significance, and greater predictive value of thyroid fine needle aspirates (FNAs). This is a prospective study undertaken from May 2015 to April 2017 which included 72 clinically diagnosed cases of thyroid swellings who attended the D.Y. Patil Hospital and Research Institute, Kolhapur. Slides were stained with Haematoxylin and Eosin (H&E) and Pap smear. The microscopic diagnosis was interpreted under six categories of Bethesda. Of the 72 FNAs, 2.77% were nondiagnostic, 87.5% were benign, 0% were atypical follicular lesion of undetermined significance (AFLUS), 4.16% were suspicious for follicular neoplasm (SFN), 0% were suspicious for malignancy (SM), and 5.5% malignant. Reviewing the thyroid FNAs with the Bethesda system allowed a more specific cytological diagnosis. TBSRTC is easy, flexible with option for descriptive diagnosis whenever required. It reduces inter observer variability in reporting thyroid FNAs.

…………………………………………………………………………………………………….... Introduction:-
Thyroid swelling is common problem among south Asian population especially Indian population due to probable dietary, environmental and genetic factors. Although benign nodules far outnumber cancerous lesions, the risk of malignancy needs to be evaluated preoperatively to determine the extent of surgery. Fine needle aspiration cytology (FNAC) is the first-line diagnostic test for evaluating thyroid nodules. 1 To address terminology and other issues related to thyroid fine-needle aspiration (FNA), the National Cancer Institute(Maryland, United States) hosted the "NCI thyroid FNA State of the Science conference".
The conclusions regarding terminology and morphologic criteria from the NCI meeting led to the Bethesda Thyroid Atlas Project and from the frame work for The Bethesda System for reporting Thyroid Cytopathology (TBSRTC). 2 The project participants hope that the adoption of this flexible framework will facilitate communication among cytopathologists. endocrinologists, surgeons, radiologists and other health care providers; facilitate cytologichistologic correlation for thyroid diseases. 3
The results were consistent with study done by Mondal et al 5 in which unsatisfactory were 1.2%, Benign follicular lesion were 87.5%, AFLUS were 1%, FN/SN were 4.2%, 1.4% cases of suspicious for malignancy and Malignant were 4.7% Maximum numbers of cases were reported as benign [Category II] which were consistent with the other studies.
Maximum number of cases in this study were females (85.2%) and in the age group 21-50 years which were consistent with study done by Yassa et al. 6 In this study the rate of nondiagnostic category was found to be 2.2% whereas in other studies it ranged from 1 to 18%. Ali suggested that the rate of non diagnostic should be limited to <10% which is consistent with this study. 7 In this study benign cases were total 87.5%. In other studies this category ranged only from 59 to 87%; but still they were maximum in number with their respective studies. The difference in the rate of benign category in these was explained by Jo et al 8 ; by the fact that these studies have been in tertiary care centers, where patients come only on a referral basis and, hence, are not exactly representative of general population.

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In this study the rate of follicular neoplasm was found to be 4.16%, whereas in other studies it range from 4 to 20 %. The results were consistence with studies done by Mondal et al 5 and Renuka et all 9 .
In this study total 4 cases were found to be papillary thyroid carcinoma and the rate was found to be 5.55%, whereas in other studies it ranged from 3 to 7%.This is the least controversial of the diagnostic total categories. The risk of malignancy is 97-100%. The results were consistent with study done by Renuka et al 9 and Bhasin et al. 10

Conclusion:-
Reviewing the thyroid FNAs with the Bethesda system allowed a more specific cytological diagnosis. The distribution of cases in the Bethesda categories differed from some studies, benign cases being higher and the number of non-diagnostic and AFLUS cases being lower. The malignancy risk for each category correlated well with other studies. The Bethesda system thus allows standardization in reporting, improves perceptions of diagnostic terminology between cytopathologists and clinicians, and leads to more consistent management approaches.