Thyroid Research and Practice

ORIGINAL ARTICLE
Year
: 2016  |  Volume : 13  |  Issue : 3  |  Page : 110--114

Better thyroid cytopathology reporting and interpretation using different classification systems


Vivek Gupta1, Arvind Bhake1, Seema Dayal2,  
1 Department of Pathology, Jawaharlal Nehru Medical College, Wardha, Maharashtra, India
2 Department of Pathology, U. P. Rural Institute of Medical Sciences and Research, Etawah, Uttar Pradesh, India

Correspondence Address:
Vivek Gupta
Department of Pathology, Jawaharlal Nehru Medical College, Sawangi (Meghe), Wardha - 442 002, Maharashtra
India

Abstract

Context: Palpable thyroid nodules may be found in 4-7% of the general population and can be approached by fine needle aspiration cytology (FNAC). Standardized terminology for thyroid cytopathology reporting is due need of the time. Aims: To (1) classify various thyroid lesions in Bethesda reporting pattern. (2) Classify the various thyroid lesions in the UK the British Thyroid Association/The Royal College Pathologist (BTA/RCP) Thy 1−Thy 5 categories. (3) Compare the results of both systems with old conventional system of reporting. Settings and Design: UP Rural Institute of Medical Sciences and Research, Saifai, Etawah and Jawaharlal Nehru Medical College, Sawangi, Wardha. Subjects and Methods: Totally, 300 thyroid lesions who attended the pathology department of both colleges were taken and classified in different classification systems, and their comparative analysis was done. Statistical Analysis Used: SPSS. Results: Total number of patients was 300. The age range was 10-70 years for both genders. Maximum Number of cases was in 20-29 years of age. The conventional reporting pattern classified 33 cases as inadequate, 233 cases as benign, Follicular adenoma 10 cases, indeterminate 13 cases, and malignancy 11 cases. In the Bethesda System of thyroid cytopathology, there were 234 cases, 6 cases, 9 cases, 3 cases, and 15 cases in category II, III, IV, V, VI, respectively. The RCP Thy 1−Thy 5 categories included 18 cases in Thy 1, 15 cases in Thy 1c, 171 cases in Thy 2, 63 cases in Thy 2c, 6 in Thy 3a, 9 in Thy 3f, 3 in Thy 4, and 15 in Thy 5 categories, respectively. Conclusions: The Bethesda System of thyroid classification and UK the BTA/RCP has superior edge over the conventional reporting pattern and should be followed more commonly and should be incorporated in routine reporting pattern for thyroid FNAC.



How to cite this article:
Gupta V, Bhake A, Dayal S. Better thyroid cytopathology reporting and interpretation using different classification systems.Thyroid Res Pract 2016;13:110-114


How to cite this URL:
Gupta V, Bhake A, Dayal S. Better thyroid cytopathology reporting and interpretation using different classification systems. Thyroid Res Pract [serial online] 2016 [cited 2022 Sep 29 ];13:110-114
Available from: https://www.thetrp.net/text.asp?2016/13/3/110/193129


Full Text

 INTRODUCTION



Palpable thyroid nodules may be found in 4-7% of the general population, and this prevalence may approach 60% when high-resolution ultrasonography is used. [1],[2],[3] Thyroid nodules can be approached by fine needle aspiration cytology (FNAC) which is a well-established technique for preoperative investigation of thyroid nodules. The technique is a noninvasive, cost-effective, and efficient method in the investigation of solitary thyroid nodules. [4],[5] About 70% to 80% of FNAC specimens from the thyroid can be classified as benign or malignant with a negative predictive value for a benign diagnosis of 92% and a positive predictive value for a malignant diagnosis of up to 100% in some series. [6]

However, until recently, there was no standardized terminology for FNA reporting. [7] The recent developments in the reporting system of thyroid FNAC due to the need of the time because thyroid nodules are becoming more common day by day; however, thyroid cancer is still comparatively rare. [8]

Consequently, to the best of our knowledge, there are no studies in the literature that address the comparison of three classification system: The old conventional reporting system followed in the institutes, The Bethesda System for reporting thyroid cytopathology (TBSRTC) and the reporting system suggested by UK the British Thyroid Association/The Royal College Pathologist (BTA/RCP). Therefore, the present study is aimed to:

Classify various thyroid lesions in Bethesda reporting patternClassify the various thyroid lesions in the UK the BTA/RCP Thy 1−Thy 5 categoriesCompare the results of both systems with old conventional system of reporting.

 SUBJECTS AND METHODS



The present study was conducted in UP Rural Institute of Medical Sciences and Research, Saifai, Etawah and Jawaharlal Nehru Medical College, Sawangi, Wardha. It is an analytical cross-sectional study design with a sample size of 300 patients who underwent thyroid FNAC on outpatient department basis. Clinically, the patients presented with swelling in any or both lobes of thyroid on palpation. Informed consent was taken before performing the procedure. Age, gender, and diagnosis were recorded. Some patients underwent thyroid scan. The patients who were already diagnosed thyroid lesions were not included in this study. For most of the patients, both Papanicolaou stained and Romanowsky (Diff-Quick) stained smears were available. The smears were studied and classified according to different classification systems and grouped in different categories. All the data were analyzed in SPSS software version 13.0 (IBM, USA).

Group A followed the conventional system according to which cytological diagnosis was categorized into the following five categories:

Unsatisfactory smears: When smears are hemorrhagic or containing less than six groups of well-preserved follicular cells on each of at least two slidesBenign or negative for malignancy: This group included thyroid cysts, colloid goiters, thyroiditis, and hyperplasia, benign when aspirates were hypocellular to moderately cellular with moderate to abundant colloid and follicular cells with round nuclei of uniform sizeFollicular lesions: Aspirates of follicular patterned lesions other than follicular variant of papillary carcinoma; (aspirates of processes that cannot be fully classified by FNAC as they require histological assessment for actual classification)Indeterminate: Aspirates showing some but not all features of malignancy that is cell clusters with enlarged and grooved nuclei without true pseudo inclusions; and the indeterminate group included follicular neoplasm's, Hurthle cell neoplasm's, and suspicious thyroid carcinomaPositive for malignancy: Any malignant category.Group B was assigned to report thyroid FNAC by the Bethesda System having the following six categories. [9]

Nondiagnostic or unsatisfactory (Bethesda I): Cyst fluid only virtually a cellular specimen other (obscuring blood, clotting artifact, etc.)Benign (Bethesda II): 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 (sub-acute) thyroiditis othersAtypical of undetermined significance or follicular lesion of undetermined significance (Bethesda III)Follicular neoplasm or suspicious for a follicular neoplasm (Bethesda IV) specify if Hürthle cell (oncocytic) typeSuspicious for malignancy (Bethesda V): Suspicious for papillary carcinoma, suspicious for medullar carcinoma, suspicious for metastatic carcinoma, and suspicious for lymphomaMalignant (Bethesda VI): Papillary thyroid carcinoma, poorly differentiated carcinoma, medullar thyroid carcinoma, undifferentiated (anaplastic) carcinoma, squamous cell carcinoma, carcinoma with mixed features (specify), metastatic carcinoma, non-Hodgkin lymphoma, or others.Group C was assigned to report thyroid FNAC in the UK the BTA/RCP Thy 1 − Thy 5 categories. [10],[11],[12]

Nondiagnostic for cytological diagnosis (Thy 1), nondiagnostic for cytological diagnosis - cystic lesion (Thy 1c)Nonneoplastic (Thy 2), nonneoplastic, cystic lesion (Thy 2c)Neoplasm possible - atypia/nondiagnostic (Thy 3a), neoplasm possible, suggesting follicular neoplasm (Thy 3f)Suspicious of malignancy (Thy 4)Malignant (Thy 5).

 RESULTS



Total number of patients was 300. The age range was 10-70 years for both genders. Maximum number of cases was in 20-29 years of age with overall male to female ratio of 2:8. The conventional reporting pattern classified 33 cases as inadequate, 233 cases as benign (colloid goiter 171 cases, Hashimito's thyroiditis 21 cases, granulomatous thyroiditis 9 cases, and others as 32 cases), Follicular adenoma 10 cases, indeterminate including suspicious 13 cases, and malignancy 11 cases (papillary 10 and medullary 1) [Figure 1].{Figure 1}

The Bethesda System of thyroid cytopathology classified cases in its different categories [Figure 2]. Benign category included 233 cases of which, 108 cases were colloid nodule, 33 cases were adenomatoid nodule, 21 cases were Hashimoto's thyroiditis, 9 cases were granulomatous thyroiditis, other 62 cases included colloid cyst, de Quervain's thyroiditis, etc. Bethesda III included 6 cases, Bethesda IV and V included 9 and 3 cases, respectively. Malignant lesions were found in 15 cases (12 papillary carcinoma, 2 medullar carcinoma and 1 anaplastic carcinoma).{Figure 2}

The thyroid lesions were also classified in the UK the BTA/RCP Thy 1−Thy 5 categories [Figure 3]. Thy 1 included 18 cases, Thy 1c included 15 cases, Thy 2 included 171 case, Thy 2c included 63, Thy 3a 6 cases, Thy 3f 9 cases, Thy 4 3 cases, and Thy 5 included 15 cases. Among Thy 5 category, 12 cases were of papillary carcinoma, 2 cases of medullary carcinoma, and 1 anaplastic carcinoma.{Figure 3}

A comparative analysis of all the three groups was also made as shown in [Table 1]. Number of unsatisfactory cases was same in all the groups. Total Concordance was observed in 277 cases of total 300 cases in different categories. Concordance was observed in 224 cases in benign category of Group A, Bethesda II of Group B and Thy 2 and 2c category of Group C. In the benign lesions, of 10 discordant cases, 3 were classified as follicular lesion, and 7 as indeterminate. Four cases were equivalent in follicular lesions or follicular lesions of undermined significance Bethesda III or Thy 3a category. Conventional reporting failed to place 3 cases in benign category and 3 in suspicious of neoplasm Bethesda IV or follicular neoplasm Bethesda V. Thirteen cases were placed in indeterminate category of which, 6 cases were only correctly placed that is, in Bethesda IV or Thy 3f category. Four malignant cases were missed in conventional reporting pattern (Group A) but were correctly identified in Bethesda VI and Thy 5 category.{Table 1}

Group B and Group C showed some equivalent categories that is, Bethesda I has equal number of cases in that of Thy 1 and 1c. The number of cases in Bethesda II is equivalent to that of Thy 2 and 2c; similarly, there are equal number of cases in Bethesda III and Thy 3a, Bethesda IV and Thy 3f, Bethesda V and Thy 4 and Bethesda VI and Thy 5.

 DISCUSSION



Interpretation of thyroid FNA is challenging because there is comparatively little difference in the morphologic features of the many nonneoplastic and neoplastic conditions of the thyroid, and there is variability in FNA specimen preparation and interpretation. Thyroid FNA has traditionally been performed by various aspirators: Endocrinologists, surgeons, radiologists, and cytopathologists, resulting in variable specimen quality. Before TBSRTC was introduced, reports were largely descriptive, with a multiplicity of category names, descriptive reports (no categories), or the use of surgical pathology terminology.

The percentage distribution if our cases in Bethesda System was in accordance with the results of other study conducted by Mondal et al. [13] The criteria of unsatisfactory smears were same in all the groups, so the number of case was same in all groups.

Four of the cases were classified as benign in Group A which turned out to be malignant and were place in Bethesda VI or Thy 5. These cases were initially placed in Thy 2c category followed later on second aspiration turned out to be papillary carcinoma. The RCP Thy 1−Thy 5 categories system clearly indicates nonconfirmatory diagnosis and allows it to be in "audit" [12] and similarly Bethesda System keeps such cases in benign category and clinical follow-up is advised. [10] Thus, there is definite advantage of the RCP Thy categories and Bethesda System over conventional reporting pattern.

Two cases classified as Benign in Group A were found to exhibit cytological atypia that raise the possibility of neoplasia but were insufficient to enable to place them confidently in any other category and were classified as Bethesda III/Thy 3a in Groups B and C, respectively.

One case in benign category in Group A was diagnosed as Hashimoto thyroiditis and was labeled as Hurthle cell neoplasm; Bethesda IV/Thy 3f in Groups B and C possibly because Hurthle cell nodule may occur in Hashimoto thyroiditis. [14] Three cases were labeled as follicular lesions in Group A but were categorized as follicular hyperplasia that is, Bethesda II in Group B and Thy 2 in Group C.

One case classified as follicular lesions in Group A had thick chewing gum colloid, but absence clear nuclear features like nuclear grooving and nuclear inclusions labeled as suspicious of papillary carcinoma and was classified as Bethesda IV/Thy 3f.

Seven cases classified as indeterminate in Group A were classified as follows: Hurthle cell neoplasm 3 cases, Psammoma bodies were seen in 1 case, nuclear groves and inclusion were seen in 2 cases and 1 case showed loose fibrous stroma containing groups of follicular cells. The pathogenic overlap occurs between Hashimoto thyroiditis and Hurthle cell neoplasm as reported earlier. [15] Psammoma bodies strongly indicative of papillary carcinoma may also be seen in multinodular goiter as has been reported. [16] Nuclear groves and inclusion may also be seen in multinodular goiter as reported earlier. [17] Perhaps all these reason may have caused problems in classification in different groups.

Sensitivity and specificity of conventional reporting pattern in case of benign lesions was 95.7% and 72.7%, respectively. Sensitivity and specificity of conventional reporting pattern in case of malignant lesions was 73.3% and 100%, respectively. Overall diagnostic accuracy was 92.7%.

Redman et al. [7] studied perceptions of diagnostic terminology and cytopathologic reporting of thyroid FNA by pathologists and clinicians and found that practice among pathologists varied. Reporting in the Bethesda System and UK the BTA/RCP system is more approachable and has definite advantage in classification of lesions, treatment and follow-up of lesions which otherwise are problematic areas in conventional reporting pattern. It has been reported that the risk of malignancy in the Bethesda categories is 1-4%, 0-3%, 5-15%, 15-30% and 60-75% in I-V, respectively. [18] Likewise Thy 2 and 2c need clinical follow-up at 6-18 months, Thy 3a needs a repeat FNAC after 3 months and subsequent surgical consultation; Thy 3f, Thy 4, Thy 5 need surgical consultation. [19]

Thus, the Bethesda System of thyroid classification and UK the BTA/RCP has superior edge over the conventional reporting pattern and should be followed more commonly and in should be incorporated in routine reporting pattern for thyroid FNAC.

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