Evaluation of FNAC Thyroid Smears Using Bethesda System For Reporting Thyroid Cytopathology Nomenclature With Clinicopathological Correlation

Original Article Evaluation of FNAC Thyroid Smears Using Bethesda System For Reporting Thyroid Cytopathology Nomenclature With Clinicopathological Correlation Shamim Ahmad Ansari*, Reeni Malik, Pramila Jain GMC & Assiociated Hospital Bhopal DOI: 10.21276/APALM.3186 *Corresponding Author: Shamim Ahmad Ansari shamim2289@gmail.com Submitted: 31-May-2022 Final Revision: 10-Dec-2022 Acceptance: 03-Jul-2023 Publication: 02-Aug-2023 This work is licensed under the Creative Commons Attribution 4.0 License. Published by Pacific Group of e-Journals (PaGe) Abstract Background: The study aimed to interpret thyroid cytology by the Bethesda System for reporting thyroid cytology (TBSRTC) and to analyze the distribution of lesions under various diagnostic categories and subcategories. Methodology: This study was conducted as an observational study at tertiary care centre on patients with thyroid lesions. After history taking and detailed local, general and systemic examination, thyroid function tests were conducted. Apart from this, ultrasonography of lesion was done. Patients were subjected to FNAC and after fixation smears were stained with Papanicolaou stain. Results: About 53% thyroid lesions were hemorrhagic, followed by 17% blood mixed colloid and 4% colorless serous fluid. Sample adequacy was noted in 93.5% cases in our study. According to Bethesda system of classification, majority of lesions were benign (81.5%) whereas 6.5% lesions were unsatisfactory. Only 6% lesions were categorsied as malignant. Conclusion: FNAC is widely accepted as the most accurate, sensitive, specific, and costeffective diagnostic procedure in the preoperative assessment of thyroid nodules. It is the first line of investigation and can differentiate benign nodules from malignant nodules of the thyroid in 95% cases. Applying a standard reporting system for thyroid cytology may enhance the communication between pathologists and clinicians, assists them to find out the rate of malignancy in each cytological group, and facilitating a more reliable approach for patient management. Keywords: FNAC, Bethesda, thyroid nodules, neoplastic, benign Introduction The thyroid is the largest endocrine gland situated superficially in the neck. The main function of this gland is to regulate various metabolic activities by Thyroxin which is mediated by the Pituitary and Hypothalamus by TSH and TRH. Diseases of the thyroid are common and associated with excess release of thyroid hormone (Hyperthyroidism), hormone deficiency (Hypothyroidism), www.pacificejournals.com/apalm eISSN: 2349-6983; pISSN: 2394-6466 Evaluation of FNAC Thyroid Smears A-20 and mass lesions of the thyroid.[1] Thyroid nodules are common and it is estimated that around 67 % of people may have one or more thyroid nodules that are otherwise no palpable or asymptomatic.[2] Risk factors include iodine-deficient areas, elder age groups, women and patients with a history of neck irradiation. Most nodules are asymptomatic and may present with symptoms ranging from swelling (goiter) to hoarseness of voice, dysphagia, and pain in the neck when their size grows and starts to compress regional structures in the throat and neck.[3] Thyroid nodules are mostly benign and very few of them are malignant. Neoplastic lesions are relatively uncommon and constitute only 0.7% in females and 0.2% in males. But in recent times there has been an increase in the incidence of thyroid neoplasm worldwide and India.[4] Thorough clinical history and examinations, ultrasonography, biochemical profile (T3,T4,TSH), Radioisotope scan, thyroid antibodies, FNAC, histopathology, and IHC studies are helpful in establishing etiological diagnosis. FNAC has proven the most cost-effective, safe, simple, and minimally invasive procedure for the evaluation of thyroid nodules.[5] In FNA cytology approx. 60% of nodules are classified as benign, <10% are malignant and 30% are not fitted in both the category and termed 'indeterminate', 'atypical', 'rule out', or 'cannot exclude malignancy'. Lack of uniform reporting systems among various laboratories leads to diagnostic confusion among pathologists and clinicians for risk management.[6] A uniform nomenclature system was proposed at the NCI conference which was subsequently known as 'The Bethesda system for reporting thyroid cytopathology' (TBSRTC).[6] TBSRTC is recognized as a standardized, category-based reporting system for thyroid fine-needle aspiration (FNA) specimens. Every thyroid FNA report should begin with one of six diagnostic categories. Every diagnostic category consists of implied cancer risk that ranges from 0% to 3% for the ''benign'' category to virtually 100% for the ''malignant'' category. This six-tiered Bethesda system provides a standardized system for thyroid smears reporting and facilitates better communication between clinicians and pathologists. The advantage of this approach is that each category has an implicit risk of malignancy which helps clinicians to plan appropriate therapy for the patient.[6] The present study aimed to interpret thyroid cytology by the Bethesda System for reporting thyroid cytology (TBSRTC) and to analyze the distribution of lesions under various diagnostic categories and subcategories. Materials and Methods This study was conducted as an observational study in the Department of Pathology, Gandhi Medical College and Jawahar Lal Nehru Cancer hospital Bhopal during the two years from October 2018 to 30th June 2020. All those patients having thyroid lesions, irrespective of their age and sex, referred for FNAC from Surgery and ENT OPD/ ward were included whereas patients with a skin infection at the site of aspiration; patients with hemorrhagic diathesis; critically ill or anxious patients and noncooperative patients were excluded from the study. The study was approved by the Institute’s ethical committee and written consent was obtained from all the study participants after explaining them nature and purpose of study. Sociodemographic details such as age, gender, education, occupation and residence was obtained from all the patients and entered in questionnaire. Clinical history in detail was obtained from all the study participants regarding presenting complaints, duration of illness, history of dysphagia, dysphonia, hoarseness of voice. Menstrual history was obtained in females. Family history, drug history was also obtained from all the patients and documented. Further, all the patients were subjected to local and general examination. Site, size, shape and type of thyroid nodule was observed. Presence of tenderness, consistency, mobility and lymphadenopathy were assessed and findings were documented. All the patients were then subjected to detailed systemic examination. Thyroid function tests were conducted when required. Ultrasonography of Annals of Pathology and Laboratory Medicine, Vol. 10, Issue 4, Aug 2023 A-21 Ansari et al. thyroid was done to establish USG diagnosis. All the patients were then subjected to FNAC of thyroid nodule. Aspirations were done by one of the following techniques -Orell SR and Vielh;[7] Sanchez MA and Stahl RE.[8] Manual pressure was applied at the site of puncture for at least five minutes. Nature of aspirate was observed and tongue shaped smears were prepared on clean glass slides with the help of another glass slide on the middle third of the slide. After the procedure slides was fixed in isopropyl alcohol for 15 minutes. After fixation smears were stained with Papanicolaou stain.[9] After staining the smears were examined and cytological diagnosis is made and interpreted according to the Bethesda reporting system.[6] Statistical analysis Data was compiled using MsExcel and analysed using IBM SPSS software version 20. Data was categorized and expressed as frequency and proportions whereas continuous variables were expressed as mean and standard deviation.Gross examination showed a nodule located in the dermis and subcutis measuring approximately 1.2 × 1 cm in size. The sectioned surface of the mass was gray, yellow. Results A total of 200 cases with thyroid nodules fulfilling the inclusion criteria were included in our study with mean age of 39.96±15.37 (Range- 8 to 84 years). Female preponderance for thyroid nodule was observed with Female to male ratio 5.67:1 and 85% (n=170) cases were females. Most common clinical Symptom observed in these patients was swelling in the neck which was present in a total of 198 cases i.e., 99% of cases followed by dysphagia in 20 cases (10 %) in which 4 of them turned out to be malignant. Cervical lymph nodes were palpable in 5 cases in which two of which turned out to be Papillary thyroid carcinoma. No thyroid swelling palpated in two cases. Duration of symptoms was less than 6 months in 45% cases whereas 55% cases presented with duration of symptoms of more than 6 months. Table 1: Distribution according to thyroid nodule characteristics Characteristics of thyroid nodules No. of cases (n=200) Percentage Site of lesion Right lobe Left lobe Bilateral(diffuse) Mid thyroid (Isthmus) <1 cm 1-3 cms 4-5 cms >5 cms Soft Firm Mixed Hard Mobile Non- Mobile Tender Non- tender Single nodule Multiple nodules 131 38 13 18 10 129 50 8 100 81 8 11 187 13 23 177 173 12 65.5% 19% 6.5% 9% 5% 64.5% 25% 4% 50% 40.5% 4% 5.5% 93.5% 6.5% 11.5% 88.5% 86.5 % 6% Diffuse 15 7.5% Size Consistency Mobility Tenderness Nodularity Right lobe involvements was most common (65.5%) and size of nodule ranged between 1 and 3 cms in majority i.e. 64.5% cases. www.pacificejournals.com/apalm eISSN: 2349-6983; pISSN: 2394-6466 Evaluation of FNAC Thyroid Smears A-22 Consistency was soft in 50% cases and nodule was mobile in 93.5% cases. Only 13 cases were fixed on palpation in which 10 cases turned out to be malignant. Majority of cases (88.5%) were not associated with tenderness. Most common type of presentation was solitary thyroid nodule (86.5%). Thyroid function tests were done in 127 cases, of them, 85% cases were euthyroid and 11.1% and 3.9% cases were hyperthyroid and hypothyroid respectively. Table 2: Distribution according to USG and cytological diagnosis USG Diagnosis and FNAC characteristics USG Nature of aspirate Sample adequacy Colloid goiter Multinodular goiter Thyroiditis Hyperplastic nodule Thyroglossal cyst Solitary thyroid nodule Neoplasm (adenoma and malignancy) Cystic lesion Other non-specific (bulky mass, hyperechoic lesion, hypoechoic lesion) Hemorrhagic aspirate Blood mixed colloid Frank colloid Serous fluid Satisfactory Unsatisfactory No. of (n=200) 92 16 24 02 04 02 23 04 33 cases 106 34 52 08 187 13 Percentage 46% 8% 12% 1% 2% 1% 11.5% 2% 16.5% 53% 17% 26% 4% 93.5% 6.5% Maximum number of thyroid cases were diagnosed as Colloid goiter (46%) on USG. Thyroiditis was diagnosed in 12% of cases. About 53% thyroid lesions were hemorrhagic, followed by 17% blood mixed colloid and 4% colorless serous fluid. Sample adequacy was noted in 93.5% cases in our study. The Fine needle aspiration smears which were adequate for evaluation were categorized into non-neoplastic and neoplastic lesions. The non-neoplastic lesions constituted a major proportion Annals of Pathology and Laboratory Medicine, Vol. 10, Issue 4, Aug 2023 A-23 Ansari et al. (96.37%). Table 3: Distribution of lesions according to the Bethesda system Group Diagnostic categories No of cases (n=200) Percentage I II III Non-Diagnostic Unsatisfactory Benign Atypia of undetermined significance or Follicular Lesion of Undetermined significance 13 163 0 6.50 81.5 0 IV Follicular neoplasm or Suspicious for a Follicular Neoplasm Hurthle cell variant 12 6.0 V VI Suspicious for malignancy Malignant 0 12 0 6.0 According to Bethesda system of classification, the majority of lesions were benign (81.5%) whereas 6.5% lesions were unsatisfactory. Only 6% lesions were categorsied as malignant. Table 4: Distribution of lesions according to various categories of Bethesda Group I (n=13) II (n=163) Lesions Hemorrhagic smears Cystic lesion Colloid goiter Colloid goiter with cystic degeneration Hyperplastic nodule Lymphocytic Thyroiditis including No of cases 04 09 52 42 37 20 Percentage 30.77 69.23 31.90 25.76 22.67 12.26 Subacute Thyroiditis Thyroglossal cyst 07 03 01 4.29 1.84 0.61 Acute Thyroiditis 01 0.61 FN/SFN 12 50 Papillary carcinoma 08 66.7 Medullary carcinoma 02 16.7 Anaplastic carcinoma 02 16.7 Cystic lesion comprises a major proportion in category-I cases (69.23%). Among category II cases, colloid goiter was maximum IV (n=12) VI (n=12) with 52 cases followed by colloid goiter with cystic degeneration 42 cases. Among malignant lesions, 66.7% were papillary carcinoma. www.pacificejournals.com/apalm eISSN: 2349-6983; pISSN: 2394-6466 A-24 Evaluation of FNAC Thyroid Smears Fig 1: Bethesda category-I, Cystic lesion:-FNA smear of 35 year female showing Fig 2: Bethesda category-II , Colloid goiter :- Glass cracking appearance of colloid seen Fig 3: Bethesda category- II,Nodular Colloid goitre:- Thyroid follicles with background of abundant colloid Annals of Pathology and Laboratory Medicine, Vol. 10, Issue 4, Aug 2023 A-25 Ansari et al. Fig 4: Colloid goiter with cystic degeneration:- Thyroid follicles admixed with hemosiderin laden macrophages Fig 5: Hyperplastic nodule:- Thyroid follicles arranged in honeycomb appearance. Mild anisonucleosis also seen. Fig 6: Hyperplastic nodule:- Sheets of thyroid follicles seen in a haemorragic background www.pacificejournals.com/apalm eISSN: 2349-6983; pISSN: 2394-6466 Evaluation of FNAC Thyroid Smears A-26 Discussion In this study, fine needle aspirations of the thyroid were analyzed and interpreted according to the six-tier category system of Bethesda classification. The Bethesda System for Reporting Thyroid Cytopathology was modified in 2017 and included a six diagnostic categories. This system was incorporated to maintain uniformity in categorization of thyroid nodular swellings.[6] In our study, 200 cases with thyroid nodules were enrolled. Mean age of patients with thyroid nodules was 39.96 years in our study. It is a well-known fact that thyroid lesions are prevalent in females as in our study (5.6 times more as compared to males). In our study, nodular swelling involving right lobe of thyroid were the predominant one (65.5%). Liechty et al[10] noticed that there was a predilection for benign and malignant nodules to occur in the right lobe compared to the left lobe. The present study like Sengupta et al[11] shows that the right lobe involvement of thyroid lesions was observed maximum in 65.5% cases. The nodule detection by palpation depends on its location within the thyroid gland, on the patient's neck, and early detection yields a better outcome. Hence, we followed the clinical examination by palpation. In our study, the majority of the patients had nodular swelling ranging 1 to 3 cms. The size of the smallest thyroid swelling was 0.5 x 0.5 cms and the largest swelling was 9x 8 cms. We observed that greater the size of nodule higher was the risk of malignancy. In agreement with our result, Kamran et al[12] reported that greater nodule size influences cancer risk, although the increase in absolute risk between small (1.0 1.9 cm) and large (4.0 cm) nodules is modest. Notably, a threshold effect is detected at 2.0 cm in nodule diameter. Thereafter, larger nodule size imparts no further malignant risk, even if 4.0 cm or larger.[12] Smith-Bindman et al[13] reported that malignancy is more common in thyroid nodules with a diameter of more than 2 cm. The consistency of normal thyroid is rubbery. In our study, 50% cases had soft consistency of the swelling which is comparable with Kirdak et al.[14] In total 24 neoplastic lesions categorized under the Bethesda system (Cat II & Cat IV), 8 cases (33%) had hard thyroid swelling. Here hardness is not conclusive but an important indicator for malignancy. It is supported by various authors.[15,16] The reason for the upward mobility of the neck swellings like thyroid lumps with deglutition is due to the relation of neck swellings to the trachea. If swelling is fixed to the trachea then it will move when the trachea moves. The process of swallowing elevates the trachea. One must observe the neck lump as the patient swallows.[17] In our study, 93.5 % of thyroid swelling was mobile with deglutition. Only 13 (6.5%) cases were fixed on palpation in which 10 cases turned out to be malignant. FNAC will help to avoid unnecessary surgery in patients with benign lesions and to reduce the cost of care, thereby improving the overall quality of life for patients with thyroid nodules. FNAC cannot differentiate follicular adenoma from follicular carcinoma, which is a major limitation of this procedure. In the present study, the majority of patients(85%) have euthyroid status irrespective of the Bethesda category however all cases showing hyperthyroid status were from Category-II and also all hypothyroid cases. All neoplastic lesions were presented as euthyroid status. No significant correlation was found. Aspirate obtained most of the time from thyroid sampling in our study was hemorrhagic (53 %), followed by frank colloid (17%). Jayaram G et al[18] suggested that the average number of needle passes recommended for adequate a sampling of thyroid lumps is two to five. As the thyroid gland is a highly vascular organ, with each impending trauma the chances of aspirating hemorrhagic fluid rises each time, so they advised to keep the number of aspirates to a minimum. Table 5 represents the comparison of Bethesda system with various studies. Annals of Pathology and Laboratory Medicine, Vol. 10, Issue 4, Aug 2023 A-27 Ansari et al. Table 5: Percentage Comparison of various studies with Bethesda (%) Studies I II III IV V VI Yassa et al[19] Nayar et al[20] Mondal et al[21] Present study 7 5 1.2 6.50 66 64 87.5 81.5 4 18 1 0 9 2 1.4 0 5 5 4.7 6 9 6 4.2 6 Histopathological and IHC data were not available of our cases. So Cyto-Histo correlation has not done. It was the major limiting factor of this study. Conclusion FNAC is widely accepted as the most accurate, sensitive, specific, and cost- effective diagnostic procedure in the preoperative assessment of thyroid nodules. It is the first line of investigation and can differentiate benign nodules from malignant nodules of the thyroid in 95% cases. Applying a standard reporting system for thyroid cytology may enhance the communication between pathologists and clinicians, assists them to find out the rate of malignancy in each cytological group, and facilitating a more reliable approach for patient management. References 1. King TW. Observations in the Thyroid gland. Guys Hosp Rep. 1836;1:429. 2. Tan GH, Gharib H. Thyroid incidentalomas: management approaches to nonpalpable nodules discovered incidentally on thyroid imaging. Ann Intern Med. 1997;126:226-31. 3. Mandel SJA. 64-year-old woman with a thyroid nodule. JAMA. 2004;292:2632-42. 4. Kishore N, Shrivastava A, Sharma LK, Chumber S, Kochupillai N, Griwan MS. Thyroid neoplasm. A profile. Indian J Surg. 1996;58:143-8. 5. Gharib H, Papini E, Paschke R, Duick DS, Valcavi R, Hegedüs L, Vitti P. American Association of Clinical Endocrinologists, Associazione Medici Endocrinologi, and European Thyroid Association medical guidelines for clinical practice for the diagnosis and management of thyroid nodules: executive summary of recommendations. J Endocrinol Invest. 2010 May;33(5):287-91. 6. Cibas ES, Ali SZ. Conference NTFSotS. The Bethesda System For Reporting Thyroid Cytopathology. Am J Clin Pathol. 2009;132:658-65. 7. Orell SR, Sterrett GF, Whitaker D, Vielh P. Techniques of FNA cytology. Fine Needle Aspiration Cytology. 5th ed. New Delhi: Elsevier India Pvt. Ltd.; 2011. p. 8-27. 8. Sanchez MA, Stahl RE. The thyroid, parathyroid, and neck masses other than lymph nodes. Williams & Wilkins; 2006. p. 1148-85. 9. Koss LG, Durfee GR, Decker JP. Diagnostic cytology and its histopathologic bases. Obstet Gynecol. 1962 Jan 1;19(1):130. 10. Liechty RD, Graham M, Freemeyer P. Benign Solitary Thyroid Nodule. Surg Gynecol Obstet. 1965;121:571-3. 11. Sengupta A, Pal R, Kar S, Zaman FA, Sengupta S, Pal S. Fine needl aspiration cytology as the primary diagnostic tool in thyroidenlargement. J Nat Sci Biol Med. 2011;2(1):113-8. 12. Kamran SC, Marqusee E, Kim MI, Frates MC, Ritner J, Peters H, Benson CB, Doubilet PM, Cibas ES, Barletta J, Cho N. Thyroid nodule size and prediction of cancer. J Clin Endocrinol Metab. 2013 Feb 1;98(2):564-70. 13. Smith-Bindman R, Lebda P, Feldstein VA, Sellami D, Goldstein RB, Brasic N, Jin C, Kornak J. Risk of thyroid cancer based on thyroid ultrasound imaging characteristics: results of a population-based study. JAMA Intern Med. 2013 Oct www.pacificejournals.com/apalm eISSN: 2349-6983; pISSN: 2394-6466 Evaluation of FNAC Thyroid Smears A-28 28;173(19):1788-95. 14. Kirdak VR, Chintale SG, Jatale SP, Shaikh KA. Our experience of clinico-pathological study of thyroid swelling. Int J Otorhinolaryngol Head Neck Surg. 2018 Sep;4:1156. 15. Cady B, Sedgwick CE, Meissner WA, Wool MS, Salzman FA, Werber J. Risk factor analysis in differentiated thyroid cancer. Cancer. 1979 Mar;43(3):810-20. 16. Charles ND. Scintigraphic evaluation of nodular goitre. Semin Nucl Med. 1971;1:316. 17. Hathiram BT, Khattar VS. Atlas of Operative Otorhinolaryngology and Head & Neck Surgery: Facial Plastics, Cosmetics and Reconstructive Surgery. JP Medical Ltd; 2013 Mar 31. 18. Jayaram G, Orell SR. Thyroid. In: Orell SR, Sterrett GF, editors. Fine Needle Aspiration Cytology. 5th ed. Gurgaon: Reed Elsevier India Private Limited; 2012. p. 118-55. 19. Yassa L, Cibas ES, Benson CB, Frates MC, Doubilet PM, Gawande AA, Moore Jr FD, et al. Long-term assessment of a multidisciplinary approach to thyroid nodule diagnostic evaluation. Cancer Cytopathol. 2007 Dec 25;111(6):508-16. 20. Nayar R, Ivanovic M. The Bethesda system for reporting thyroid fine needle aspirates: A cytologic study with histologic follow-up. J Cytol. 2013 Apr;30(2):94. Annals of Pathology and Laboratory Medicine, Vol. 10, Issue 4, Aug 2023