|Year : 2020 | Volume
| Issue : 1 | Page : 57-62
Fine-needle aspiration cytology of thyroid nodule(s) at a tertiary hospital in West Bengal, India: A 5-year experience
Krishnendu Das1, Mausumi Basu2, Susmita Sarkar3, Sita Chatterjee4
1 Department of Pathology, Malda Medical College and Hospital, Malda, West Bengal, India
2 Department of Community Medicine, IPGME and R and SSKM Hospital, Kolkata, West Bengal, India
3 Department of Biochemistry, Malda Medical College and Hospital, Malda, West Bengal, India
4 Department of Community Medicine, KPC Medical College and Hospital, Kolkata, West Bengal, India
|Date of Submission||09-May-2019|
|Date of Decision||30-May-2019|
|Date of Acceptance||01-Jun-2019|
|Date of Web Publication||16-Dec-2019|
Department of Biochemistry, Malda Medical College and Hospital, Malda, West Bengal
Source of Support: None, Conflict of Interest: None
Introduction: Thyroid nodules are a common clinical finding which is important due to their malignant potential. Fine-needle aspiration cytology (FNAC) is routinely used for first-line diagnosis of thyroid lesions and to differentiate benign from malignant nodules. Objective: The objective was to evaluate the advantage of FNAC as a simple procedure for the diagnosis of thyroid swelling. Materials and Methods: This is a retrospective study conducted at the department of pathology of a tertiary care hospital among 681 diagnosed patients of thyroid swelling who underwent FNAC. The results were interpreted according to the Bethesda nomenclature. Results: The most common age group affected was 20–29 years (29.22%), female patients were 90.46% and that of males were 09.54%, benign cases constituted 91.63%, follicular lesion of undetermined significance were 00.33%, follicular neoplasm were 02.93%, suspicious cases were 00.44%, malignant cases were 4.40%, and unsatisfactory were 00.33%). Among benign group, 45.03% of cases were of colloid goiter and 23.72% were of Hashimoto's thyroiditis. The malignant diagnoses yielded 83.33% of papillary carcinoma, 10% of medullary carcinoma, and 3.33% of anaplastic carcinoma. Conclusion: FNAC is a rapid and cost-effective screening test for accurate diagnosis of thyroid swellings.
Keywords: Bethesda nomenclature, fine-needle aspiration cytology, thyroid nodules
|How to cite this article:|
Das K, Basu M, Sarkar S, Chatterjee S. Fine-needle aspiration cytology of thyroid nodule(s) at a tertiary hospital in West Bengal, India: A 5-year experience. Med J DY Patil Vidyapeeth 2020;13:57-62
|How to cite this URL:|
Das K, Basu M, Sarkar S, Chatterjee S. Fine-needle aspiration cytology of thyroid nodule(s) at a tertiary hospital in West Bengal, India: A 5-year experience. Med J DY Patil Vidyapeeth [serial online] 2020 [cited 2020 Jul 9];13:57-62. Available from: http://www.mjdrdypv.org/text.asp?2020/13/1/57/272874
| Introduction|| |
Thyroid nodules (TNs) are a common clinical finding which is important due to their malignant potential with 3%–7% prevalence, which is increasing. This high prevalence of TNs cannot be explained solely by traditional risk factors such as age, sex, iodine intake, and radiation exposure. It may be partly due to advancements in diagnostic technologies. However, a number of studies ,, have reported that lifestyle, obesity, and metabolic syndrome are associated with increased TN prevalence.
Nearly 5%–15% of TNs are thyroid cancer, which is the fastest growing cancer. The incidence of thyroid cancer has been increased three times from 1975 to 2009, mainly due to increase in papillary thyroid carcinoma. Thus, early diagnosis and prompt treatment has now become increasingly indispensable to cure malignant thyroid carcinoma.
The differentiation between benign and malignant TNs is crucial because malignancy needs surgery, whereas strict follow-up is necessary for a benign mass. Fine-needle aspiration cytology (FNAC) is considered the “gold standard” in the selection of patients for surgery.
FNAC is the most common method and routinely used for the first-line diagnosis of thyroid lesions. It is safe, simple, reliable, easily performed, rapid, cost-effective, minimally invasive, highly sensitive, specific, and accurate with low complication rate and has an important valuable role in the diagnosis of diffuse nontoxic goiter, to confirm the diagnosis of clinically obvious malignancy and to differentiate benign from malignant nodules. Due to its simplicity, it can be carried out in the outpatient department and can be readily repeated if necessary, and thus has a good patient compliance. Based on the FNAC findings, surgery is done in cases of malignancy, thus dramatically decreasing the rate of surgery with its consequent complications and at the same time increasing the yield of malignant lesions among patients who underwent surgery. However, like other tests, FNAC has some disadvantages such as false-negative and false-positive results and some limitations such as specimen adequacy, sampling techniques, skill of the physician, experience of the pathologist interpreting the aspirate, and the overlapping cytological features between some benign and malignant thyroid lesions.
In January 2010, The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC),, was published which was revised in 2017 by the National Cancer Institute, Bethesda, Maryland, USA, which gives a standardized, category-based reporting system for thyroid FNA specimens. As per the 2017 revision, every thyroid FNA report should begin with one of the six diagnostic categories, the names of which continue to exist since their first introduction: (i) nondiagnostic or unsatisfactory (ND/UNS); (ii) benign; (iii) atypia of undetermined significance (AUS) or follicular lesion of undetermined significance (FLUS); (iv) follicular neoplasm (FN) or suspicious for a follicular neoplasm (SFN); (v) suspicious for malignancy (SM); and (vi) malignant. A diagnostic laboratory may choose the one it prefers. Each category has a definite cancer risk which ranges from 0% to 3% for the “benign” category to 100% for the “malignant” category. In the 2017 revision, the malignancy risks were updated based on the new (post 2010) data. As per their risk associations, each category is related to updated, evidence-based clinical management recommendations. The TBSRTC is widely used in recent years to overcome ambiguities in report.
Although thyroid swellings are a very common problem in this part of India, little work has been reported regarding this. With this background, a study was conducted with cases of thyroid swellings to evaluate the advantage of FNAC as a simple procedure for the diagnosis of thyroid swelling.
| Materials and Methods|| |
The present study was a retrospective hospital-based study undertook in the department of pathology of a tertiary care hospital in West Bengal, India. The study duration and period was 5 years from January 1, 2014, till December 31, 2018. Inclusion criteria were patients with thyroid swelling who were subjected to FNAC (including guided). The sample size was 681 diagnosed patients of TN who underwent FNAC for diagnosis. After proper informed written consent was taken, a sterile 22G disposable needle, 1½” long fitted with a 10-ml syringe, was used to aspirate using standard procedure. In certain conditions, nonaspiration technique was used. May–Grünwald–Giemsa and Papanicolaou staining were done on the material aspirated, which was reviewed by three cytopathologists under a light microscope. The results were interpreted and classified according to the current recommended Bethesda nomenclature  into six groups as: insufficient for diagnosis, benign, atypical FLUS (AFLUS), FN, SM, and malignant. Insufficient cellularity or poor quality smear due to delayed or inadequate fixation was considered “unsatisfactory.” Data were cross checked, entered in Excel, presented in percentages, and expressed in tables using Epi Info software, version 7, Centers for Disease Control and Prevention, Atlanta, Georgia.
| Operational Definition|| |
The 2017 Bethesda System for Reporting Thyroid Cytopathology: Recommended Diagnostic Categories
- ND or UNS
- Cyst fluid only
- Virtually acellular specimen
- Other (obscuring blood, clotting artifact, etc.)
- Consistent with a benign follicular nodule (includes adenomatoid nodule, colloid nodule, etc.)
- Consistent with lymphocytic (Hashimoto) thyroiditis in the proper clinical context
- Consistent with granulomatous (subacute) thyroiditis
Atypical of undetermined significance (AUS) or follicular lesion of undetermined significanceFN or SFN
- Specify if Hürthle cell (oncocytic) type
- Suspicious for papillary carcinoma
- Suspicious for medullary carcinoma
- Suspicious for metastatic carcinoma
- Suspicious for lymphoma
- Papillary thyroid carcinoma
- Poorly differentiated carcinoma
- Medullary thyroid carcinoma
- Undifferentiated (anaplastic) carcinoma
- Squamous-cell carcinoma
- Carcinoma with mixed features (specify)
- Metastatic carcinoma
- Non-Hodgkin lymphoma
The 2017 Bethesda system for reporting thyroid cytopathology: Implied risk of malignancy and recommended clinical management
This classification along with the revised risk of malignancy mentioned in [Table 1] establishes a correlation between the cytology of FNA contents and the different thyroid diseases.
|Table 1: The 2017 Bethesda system for reporting thyroid cytopathology: Implied risk of malignancy and recommended clinical management in 2009 (before NIFTP) and in 2018 (after NIFTP)|
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| Results|| |
[Table 2] demonstrates the sociodemographic profile of the study population. In this study, a total of 681 patients were included. The most common age group affected was 20–29 years (29.22%) followed by 30–39 years (24.96%) and 40–49 years (21.59%). The least affected age group was below 10 years (0.73%) followed by above 80 years (00.44%). The mean age of the patients presented with thyroid lesion was 35.81 ± 14.15 years (x ± standard deviation). The distribution of females was with a frequency of 90.46% and that of males was 09.54%.
|Table 2: Distribution of the study population as per age and sex (n=681)|
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FNAC results were interpreted as benign in 624 cases (91.63%), FLUS in 2 cases (00.33%), FN in 20 cases (02.93%), suspicious in 3 cases (00.44%), malignant in 30 cases (4.40%), and UNS in 2 cases (00.33%) [Table 3].
|Table 3: Distribution of the study population as per Bethesda categories (n=681)|
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[Table 4] reveals the distribution of the study population as per cytopathological diagnosis. The benign diagnoses included 281 cases (45.03%) of nodular colloid goiter and 148 cases (23.72%) of Hashimoto's thyroiditis. The malignant diagnoses were 25 cases (83.33%) of papillary carcinoma, 3 cases (10%) of medullary carcinoma, and 1 case (03.33%) of anaplastic carcinoma.
|Table 4: Distribution of the study population as per cytopathological diagnosis (n=681)|
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| Discussion|| |
Thyroid diseases are quite common in the environment of West Bengal and present as a swelling in front of neck, which may be due to goiter, inflammation, cyst, or malignancy.
In the present study, 681 patients with thyroid swelling underwent FNAC for diagnosis, which is a sensitive and highly specific method of assessing and managing TNs.
As reported in many literatures, age and gender are the associated factors of thyroid lesions. In the present study, the peak incidence was between 20 and 39 years of age (54.18%), similar to a study conducted by Ahmed et al. at Multan (67%).
In our study, 10% of the patients were male and the rest 90% were female, with a female-to-male ratio of 9.47:1, which is similar to the Multan study  where males and females constituted 15% and 85%, respectively (5:1). Another study by Sinna and Ezzat at Egypt revealed that 16.2% of patients in their study were male and 83.8% were female, with a female-to-male ratio of 5.2:1. Females outnumbered males, with a female-to-male ratio of 4:1 in a study by Sengupta et al. at Bihar.
The nodules were more likely to be malignant at the extremes of age and in male sex.,,,
It was seen that the distribution of cases as per the six-tier Bethesda system in this study was similar to some previous studies, with the percentage of cases in the benign category being higher ,,,,,, and that in the nondiagnostic and AFLUS categories being lower.
Out of the 681 FNACs, 91.63% were benign, 0.33% were atypical FLUS (AFLUS)/atypical of undetermined significance (AUS), 2.93% were SFN, 0.44% were SM, 4.40% were malignant, and 0.33% were ND/UNS, whereas in a study by Lngegowda et al. at Salem, 89% of cases were benign and 11% were malignant.
In a study by Mondal et al. at Kolkata, the corresponding figures were 87.5% as benign, 1% as atypical FLUS (AFLUS), 4.2% as SFN, 1.4% as SM, 4.7% as malignant, and 1.2% as ND/UNS.
Another study by Nggada et al. at Nigeria demonstrated 73.9% cases of benign and 26.1% cases of malignancy or suspicious of malignancy.
In the Egypt study, 33.1% of cases were diagnosed as benign, 13.5% as follicular lesion of undetermined significance (AUS/AFLUS), 16.5% as follicular neoplasm (SFN), 10.1% as SM, 19.5% as malignant, and 7.1% as UNS.
Egypt, Nigeria, Bhopal, and Bihar studies  demonstrated that nodular colloid goiter/hyperplasia represented the majority of benign cases, whereas papillary carcinoma was the most frequent malignant lesion. These findings were similar to the present study. Many thyroid cancers, especially papillary carcinoma, can be diagnosed confidently by FNAC.
This study showed that the benign diagnoses included 281 cases (45%) of nodular colloid goiter and 148 cases (23.72%) of Hashimoto's thyroiditis. The malignant diagnoses yielded 25 cases (83.33%) of papillary carcinoma, 3 cases (10%) of medullary carcinoma, and 1 case (03.33%) of anaplastic carcinoma. Whereas in the Egypt study, the benign diagnoses were 89.8% of nodular colloid goiter and 10.2% of Hashimoto's thyroiditis. The malignant diagnoses yielded 72.4% of papillary carcinoma, 10.3% of medullary carcinoma, and 17.2% of anaplastic carcinoma.
The benign diseases of the Nigerian study included 49.3% of nodular colloid goiter, 8.7% of toxic goiter, 10.1% of follicular adenoma, and 2.9% of cases each of Hashimoto's thyroiditis and subacute thyroiditis. The malignant diagnoses yielded 10 (14.5%) cases of follicular carcinoma, 3 (4.3%) cases of medullary and papillary carcinomas, and 2 (2.9%) cases of anaplastic carcinoma.
Likhar et al. at Bhopal demonstrated that the most common thyroid lesions were benign (94.4%), followed by malignant only (2.6%), indeterminate/suspicious (1.3%), and inadequate (1.7%). Out of benign thyroid lesions, 33% constituted simple colloid goiter, 27.6% goiter with cystic changes, 16.28% nodular colloid goiter, 10.41% lymphocytic thyroiditis, 4.53% thyroglossal cyst, 4.07% colloid goiter with hemorrhage, 0.9% follicular adenoma, and others formed 3.17%. Out of malignant thyroid lesions, 50% were of papillary carcinoma and the other 50% were of FN.
Each and every thyroid FNAC should be evaluated for adequacy, and inadequate samples are reported as “nondiagnostic” or “unsatisfactory,” which means that the specimens are UNS due to obscuring blood, thick smears, air drying of alcohol-fixed smears, or inadequate number of follicular cells. Moreover, for a thyroid FNAC specimen to be satisfactory, at least six groups of benign follicular cells are required, with each group composed of at least ten cells. Published literature suggest an inadequate sample size ranging from 2% to 20%. In our study, the inadequate sample rate was only 0.3%, whereas in Egypt, it was 7.1%, and in Kolkata, it was 1.2%.
The incidence of FLUS cases in our study was only 0.3%, which was almost similar to the study conducted at Kolkata (1%), but quite lower than the reported figure of 13.5% in Egypt.
Mehra and Verma at the Employees State Insurance (ESI) Postgraduate Institute of Medical Sciences and Research and ESI Model Hospital, Basaidarapur, New Delhi, described that benign category was the largest (80%) followed by ND/UNS category (7.2%). Malignant and SFM categories constituted 2.2% and 3.6% of cases, respectively, making a total of 5.7%. AUS/FLUS constituted 4.9% of cases, whereas FN/SFN had 2.2% of cases.
Thus, we can conclude that the results of our study were comparable with other past and recent published data, and FNAC is a sensitive, a specific, a reliable, and a well-established, accurate, first-line initial investigative procedure for the evaluation of patients with thyroid swelling.
The limitation of FNAC is the presence of false-positive and false-negative results, especially in small tumors, and if there is associated inflammatory or degenerative change in the nearby thyroid tissue.
A benign FNAC diagnosis might be viewed with great caution because false-negative results can occur, and these patients might be followed up for any progress which may require repeated FNAC and/or surgery.
| Conclusion And Recommendation|| |
Our study revealed that FNAC is a useful and cost-effective screening and diagnostic technique for the assessment of TNs. Many tests can be used for the evaluation of thyroid swellings before proceeding to thyroid surgery. However, studies have shown that among all those diagnostic modalities, FNAC has been found to be the rapid and cost-effective screening test for accurate diagnosis of thyroid swellings.
Moreover, its use reduces the number of thyroidectomies by half  and the cost of medical care by one fourth  though it has a false-negative rate of about 5% and a false-positive rate of about 1%.
Another conclusion is that the Bethesda system is very useful for reporting thyroid cytopathology, improving communication between cytopathologists and clinicians, and implementing interlaboratory agreement, and thus leads to more consistent management approaches. Moreover, the high malignant risk for the AFLUS and SM categories indicates the importance of these categories in the six-tier Bethesda system.
A prospective study covering larger population would give more insight into the merits and demerits of the proposed system.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4]