|Year : 2017 | Volume
| Issue : 1 | Page : 3-7
The Bethesda system of reporting thyroid fine needle aspirates: A 2-year cytologic study in a tertiary care institute
Rajesh Singh Laishram, Tlangte Zothanmawii, Zothansung Joute, Padi Yasung, Kaushik Debnath
Department of Pathology, Regional Institute of Medical Sciences, Imphal, Manipur, India
|Date of Web Publication||17-Jan-2017|
Rajesh Singh Laishram
Department of Pathology, Regional Institute of Medical Sciences, Lamphelpat, Imphal - 795 004, Manipur
Source of Support: None, Conflict of Interest: None
Background: The Bethesda system for reporting thyroid cytopathology (TBSRTC) represents a major step in the interpretation of thyroid fine needle aspiration (FNA) creating uniformity and clarity and providing clinically relevant information assisting the referring physicians in the management of the patients. Aims: To study the cytological features of thyroid FNA and interpretation of the smears by TBSRTC. Materials and Methods: A retrospective study of thyroid FNAs from May 2013 to June 2015 is carried out in the Pathology Department of a tertiary care institute. The results are interpreted according to the features and categories given in the monograph of TBSRTC. Results: A total of 576 cases studied. The distribution of the various categories from evaluated thyroid FNAs are as follows: nondiagnostic/unsatisfactory - 5.2%, benign - 89.9%, atypia of undetermined significance - 0%, follicular neoplasm (FN) or suspicious for a FN - 2.2%, suspicious for malignancy - 0.3%, malignant - 2.2%. Conclusion: The Bethesda system allows a more standard and uniform method of reporting thyroid cytology providing a clear and consistent management guidelines for the clinicians.
Keywords: Bethesda system, follicular neoplasm, papillary carcinoma
|How to cite this article:|
Laishram RS, Zothanmawii T, Joute Z, Yasung P, Debnath K. The Bethesda system of reporting thyroid fine needle aspirates: A 2-year cytologic study in a tertiary care institute. J Med Soc 2017;31:3-7
|How to cite this URL:|
Laishram RS, Zothanmawii T, Joute Z, Yasung P, Debnath K. The Bethesda system of reporting thyroid fine needle aspirates: A 2-year cytologic study in a tertiary care institute. J Med Soc [serial online] 2017 [cited 2020 May 26];31:3-7. Available from: http://www.jmedsoc.org/text.asp?2017/31/1/3/198423
| Introduction|| |
Fine needle aspiration (FNA) of the thyroid gland was first introduced by Soderstrom in 1952.  It became widely used in many medical centers in the 1980s.  FNA plays an evolutionary role in the interpretation and evaluation of thyroid lesions. In international guidelines, high-resolution ultrasonography and FNA biopsy are recommended as the first-line evaluation tools of thyroid nodules.  Although thyroid ultrasonography is convenient and noninvasive, the ultrasound features are not adequately sensitive to detect all thyroid lesions. Hence, thyroid FNA is the most important diagnostic tool for thyroid lesions.  Routine use of FNA has significantly reduced the number of adults undergoing surgery for benign disease. , With experienced physicians performing needle biopsy, and experienced cytopathologists interpreting the results, the accuracy of FNA has been reported as 95%-97%. 
The terminology for reporting thyroid cytopathology varies markedly with the application of different category schemes. It is critical that cytopathologists communicate thyroid FNA interpretations to referring physicians in terms that are succinct, unambiguous, and clinically helpful. To address terminology and other issues related to thyroid FNA, the National Cancer Institute (NCI) hosted the "NCI Thyroid FNA State of the Science Conference," which took place on October 22 and 23, 2007, in Bethesda, Maryland.  The conclusions regarding terminology and morphologic criteria from the NCI meeting led to the Bethesda Thyroid Atlas Project and formed the framework for the Bethesda system for reporting thyroid cytopathology (TBSRTC). The NCI Thyroid Conference addressed a wide range of issues other than terminology. , TBSRTC represents a six-category scheme of reporting thyroid cytopathology, with an implied malignancy risk and a brief management plan. The risk associated category is linked to evidence-based clinical management guidelines.
The objective of this study done in the Department of Pathology of a tertiary care institute was to analyze the cytological features and group the thyroid cytopathology reports based on the diagnostic criteria of TBSRTC monograph.
| Materials And Methods|| |
A retrospective, cross-sectional study of all referred cases of thyroid swelling to the Cytology Outpatient Department, Department of Pathology of a tertiary care institute was conducted during May 2013-June 2015. Informed consent was taken from all the patients before performing the procedure. The consented patients were subjected to FNA sampling, and all the slides obtained are stained with May-Grunwald-Giemsa stain as per the standard protocol. The cytological features of the smears were evaluated and reporting was done based on the morphological criteria given in the monograph of TBSRTC. The six categories are (1) nondiagnostic/unsatisfactory (ND/UNS), (2) benign, (3) atypia of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS), (4) follicular neoplasm (FN) or suspicious for FN (SFN), (5) suspicious for malignancy (SFM), and (6) malignant.
Descriptive statistics such as mean and ratio are used for the interpretation of the study.
| Results And Observations|| |
A total of 576 cases were included in the study. There is female predominance with female:male ratio of 7.6:1, and the most common age group encountered is in the age group of 21-30 years. The age distribution ranged from 7 to 83 years, with a mean age of 49 [Table 1]. The distribution of the 576 into the six categories is shown in [Table 2]. Benign cases constitute the largest category with 89.9%, of which benign follicular nodule was the most common lesion. FN and malignant cases constituted 2.2% each. Among the malignant group, papillary carcinoma thyroid was the most common lesion with 11 cases. Out of the 13 cases of FN, only 5 cases could be followed up histopathologically. Three cases turned out to be of follicular adenoma and two cases were follicular carcinoma on histopathological examination. Among the 13 cases of malignant cases, six cases could be followed up with subsequent histopathological examination, which matched with the cytological diagnosis of papillary carcinoma[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5] and [Figure 6] .
|Table 2: Distribution of cases in various diagnostic categories and subcategories according to the Bethesda System for Reporting Thyroid Cytopathology |
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|Figure 1: Photomicrograph of fine needle aspiration thyroid smears showing an unsatisfactory smear with abundant red cells, devoid of thyroid parenchymal cells (MGG stain, ×4)|
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|Figure 2: Photomicrograph of fine needle aspiration thyroid smears showing benign lymphocytic thyroiditis with mixed population of Hurthle cells and polymorphic lymphocytes (MGG stain, ×10)|
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|Figure 3: Photomicrograph of fine needle aspiration thyroid smears showing follicular neoplasm/suspicious for a follicular neoplasm. Benign follicular cells arranged in cluster and microfollicles (MGG stain, ×10)|
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|Figure 4: Photomicrograph of fine needle aspiration thyroid smears showing papillary thyroid carcinoma. Cellular smear with papillary fragments and numerous monolayered sheets of follicular cells (MGG stain, ×10)|
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|Figure 5: Photomicrograph of fine needle aspiration thyroid smears showing papillary thyroid carcinoma having cells with fine powdery chromatin, micronucleoli, and intranuclear cytoplasmic pseudoinclusions (MGG stain, ×40)|
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|Figure 6: Photomicrograph of fine needle aspiration thyroid smears showing medullary thyroid carcinoma displaying dispersed plasmacytoid cells with variation in nuclear size and shape and amyloid (MGG stain, ×40)|
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| Discussion|| |
This study shows 2-year results of reporting thyroid aspiration by TBSRTC. The previously offered reporting system when reviewed seemed complicated and did not provide a valuable significance to the clinicians in planning of management. However, when we recorded the diagnoses as per the criteria laid down in the standardized nomenclature of the Bethesda system, it seemed more simplified, systematic, with greater clarity; thus, it would prove to be more useful in guiding clinicians toward the management of thyroid nodules.  TBSRTC does not recommend surgery for ND/UNS, benign, and AUS/FLUS categories. In the FN/SFN, SFM, and malignant categories, we expected excision of nodules or partial/complete thyroidectomy in all cases as per the TBSRTC recommendations. This system helps the clinicians in planning their course of management for their patients.
The results obtained from our present study was compared with the studies of Mondal et al.,  Jo et al.,  Yassa et al.,  Yang et al.,  and Nayar and Ivanovic.  The comparison of the results obtained is given in [Table 3]. The distribution of cases as per the TBSRTC in this study differed from the other mentioned studies with low percentage in SN/SFN, SM, and malignant categories and no cases of atypical follicular lesion of undetermined significance (AFLUS). The high percentage of cases in the benign category can be attributed to the fact that patients attended directly without referral basis. The above-mentioned studies have been carried out in tertiary care centers, thus reasoning the higher percentage of SM and malignant cases compared to our studies.
The correlation with clinical, biochemical, and radiology findings was not available for many cases, which was one of the limitations of our study. Lack of histopathological correlation in majority is the limitation of the study.
Thyroid nodules are found in 4%-10% of the adults, and their incidence has been on the rise with ultrasonographic examination.  FNA has become the accepted way to initially evaluate thyroid lesions because it is relatively easy to collect a specimen and also because it is safe. FNA cytology provides an important guideline for the treatment of thyroid nodules, by which on the one hand the risk of unnecessary surgery is reduced and on the other hand it provides an appropriate opportunity for surgery of the malignant disease. 
The role of the pathologist is to render accurate, succinct, and understandable diagnoses, so a correct therapeutic strategy or intervention can be pursued.  Many of the problems associated with understanding thyroid FNA reports is mitigated if consistent criteria and a standardized reporting system were used. In 2007, the NCI recommended TBSRTC as a means of improving the accuracy of thyroid cytopathology.  The Bethesda system standardized the system of reporting thyroid cytopathology, improving communication between cytopathologists and clinicians and interlaboratory agreement, leading to more consistent management approaches.  The high malignancy risk for the AFLUS, SM, and malignancy categories reflects the importance of these categories in the six-tier Bethesda system.
Adoption of the Bethesda system will thus allow a more standard and uniform method of reporting thyroid cytology, providing a clear and consistent management guidelines for the clinicians.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2], [Table 3]