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ORIGINAL ARTICLE
Year : 2019  |  Volume : 16  |  Issue : 3  |  Page : 105-107

Role of nuclear grooves in the cytological diagnosis of papillary carcinoma thyroid


Department of Pathology, Father Muller Medical College, Mangalore, Karnataka, India

Date of Submission30-Jul-2018
Date of Acceptance04-Oct-2019
Date of Web Publication18-Nov-2019

Correspondence Address:
Dr. Archana S Bhat
Department of Pathology, Father Muller Medical College, Mangalore - 575 002, Karnataka
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/trp.trp_39_18

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  Abstract 


Introduction: It is well known that nuclear grooves play a major role in the diagnosis of papillary carcinoma thyroid (PCT). Furthermore, grooves are found in many nonneoplastic lesions of thyroid.
Aims: The aim of this study is to calculate the percentage of nuclear grooves in histopathologically proven cases of papillary carcinoma and nonneoplastic lesions (Hashimoto's thyroiditis and colloid goiter).
Materials and Methods: This retrospective study was carried out by reviewing the data and cytology smears of 21 histopathologically confirmed cases of PCT and 10 cases each of Hashimoto's thyroiditis and colloid goiter. The percentage of nuclear grooves was calculated in oil immersion by counting 100–500 cells depending on the cellularity.
Results: The percentage of nuclear grooving ranged from 15% to 85% in the papillary carcinoma cases. Greater than 20% nuclear grooves were observed in 19 (90.4%) of the cases. Nuclear crowding and overlapping, pale chromatin, nuclear grooves, nuclear enlargement, and prominent nucleoli were seen in all (100%) cases. Intranuclear cytoplasmic pseudoinclusions were seen in only 5 (23.8%) of the cases. Histiocytes, metaplastic cells, and multinucleated giant cells were seen in 12 (57.1%), 10 (47.6%), and 6 (28.5%) of the cases. The percentage of nuclear grooves in nonneoplastic cases overall observed was <10%. The sensitivity and specificity of grooves for PCT at ≥20% were 90.5% and 100%, respectively.
Conclusion: Whenever in doubt, a diagnosis of papillary carcinoma can be offered confidently by this semiquantitative approach for grooves in combination with other features.

Keywords: Cytology, nuclear grooves, papillary carcinoma thyroid


How to cite this article:
Bhat AS, Varma L, Fernandes H, Jayaprakash C S. Role of nuclear grooves in the cytological diagnosis of papillary carcinoma thyroid. Thyroid Res Pract 2019;16:105-7

How to cite this URL:
Bhat AS, Varma L, Fernandes H, Jayaprakash C S. Role of nuclear grooves in the cytological diagnosis of papillary carcinoma thyroid. Thyroid Res Pract [serial online] 2019 [cited 2019 Dec 15];16:105-7. Available from: http://www.thetrp.net/text.asp?2019/16/3/105/271158




  Introduction Top


Fine-needle aspiration cytology is a widely accepted and sensitive diagnostic tool for thyroid lesions. Being minimally invasive test, it has gained a lot of importance as this simple test can avoid unnecessary surgical resections in a good number of cases.[1] Cytological diagnosis of papillary carcinoma thyroid (PCT) is easy and can be rendered confidently when characteristic features such as papillary fragments, unequivocal intranuclear cytoplasmic inclusions, nuclear grooves, pale chromatin, chewing colloid, and nuclear enlargement are present.[2] It is well known that nuclear grooves play a major role in the diagnosis of PCT. However, grooves can be present in many nonpapillary carcinoma lesions of thyroid as well.[3],[4],[5]


  Materials and Methods Top


This was a retrospective study of sample size 41 conducted in the Department of Pathology, Father Muller Medical College, with the approval of the Institution Ethical Clearance Committee, and included cases reported during a 2 years period from September 2013 to September 2015. The study included 21 cases of PCT, which were histopathologically confirmed. The control group included 20 cases, 10 each of Hashimoto's thyroiditis, and nodular colloid goiter. The clinical data, slides, and smears of the cases were retrieved and analyzed.

The percentage of cells exhibiting nuclear grooves was calculated by counting 100–500 cells depending on the cellularity in each case. The mean was taken. The counting was done in oil immersion (×100). The counting was done in fields exhibiting maximum cells with a grooved nucleus.

Statistics

The sensitivity and specificity were calculated using the formulae:

Sensitivity = True positive/(True positive + False negative).

Specificity = True negative/(True negative + False positive).


  Results Top


Among the 21 histopathologically confirmed cases of PCT, nuclear grooves, nuclear crowding, overlapping, pale chromatin, nucleomegaly, and prominent nucleoli were seen in all (100%) cases. Intranuclear cytoplasmic pseudoinclusions were seen in only 5(23.8%) cases.

The percentage of nuclear grooves in PCT cases ranged from as low as 15% to as high as 85%. Grooves at ≥20% were seen in 19(90.4%) of the 21 cases. Grooves at ≥10% were seen in all (100%) cases.

Among the 10 nodular colloid goitre cases, the percentage of cells with grooves ranged from 0% to 10%. Among the 10 Hashimoto's thyroiditis cases, the percentage of cells with nuclear grooves ranged from 1% to 8%.

The sensitivity and specificity of grooves for PCT at ≥20% were 90.5% and 100%, respectively.

The sensitivity and specificity of grooves for PCT at ≥10% were 100% and 95%, respectively.


  Discussion Top


The grooving of nucleus in PCT was first described in 1986 by Chan and Saw, but this was in the histopathological section.[5] The nuclear grooving was first described in fine-needle aspiration smears by Rupp and Ehya.[6]

Various studies have demonstrated the presence of nuclear grooves in nonpapillary carcinoma lesions of thyroid also.[3],[4],[5]

However, the dilemma and the controversies regarding the cutoff for considering grooving significant still remained.

In a study by Rupp and Ehya,[6] they analyzed 20 papillary carcinomas cases of the thyroid, 10 follicular adenomas, 3 follicular carcinomas, 1 medullary carcinoma, 10 nodular goiters, and 4 cases of Hashimoto's thyroiditis. In each case, 30 random high power fields or all the fields in cases with less cellularity were examined for the percentage of cells exhibiting nuclear grooving. Of the total 20 PCT cases, 17 cases (85%) showed grooving in >25% of the high power fields examined. While all the nonPCT lesions showed occasional (<25% of the high power fields) or no grooving.

Shurbaji, Frost, and Gupta conducted a study on 124 thyroid lesions which included 11 PCT cases, 01 follicular carcinoma, 06 follicular adenomas, 08 follicular neoplasms not otherwise specified, 10 cases of chronic thyroiditis, and 88 colloid nodules/adenomatous goiters.[7] Among the PCT cases, grooves were found in all the 11 cases. While among the 113 nonPCT cases, only 2 (1.8%) cases showed grooves, both of which were colloid goiters, one with extensive Hürthle cell metaplasia. They also found that grooves are better appreciated in wet fixed Papanicolaou-stained smears than air-dried diff-quick stained smears. In our study too, we found Papanicolaou-stained smears better for the identification of grooved nucleus.

In 1990, Bhambhani et al.[8] studied nuclear grooves in May-Grünwald Giemsa (MGG)-stained smears. They observed nuclear grooves in 88% of the cases of PCT. They concluded that nuclear grooves can be used as a possible marker of PCT in MGG stained smears also.

Gould et al.[9] studied 69 fine-needle aspiration smears and demonstrated grooves in 100% cases of PCT, 70% cases of nonpapillary carcinoma, and 56% of nonneoplastic thyroid cases. They estimated the percent of cells showing grooves by examining random 5 high power fields.

In another study by Yang and Demirci,[10] of the total 48 cases of histologically confirmed papillary carcinoma, nuclear grooves were found at ≥20% in 31 cases (65%) and 10%–19% in 17 cases (35%). Moreover, among the 15 cases of histologically confirmed nonneoplastic cases, 4 cases (27%) showed 10%–19% cells with nuclear grooves, whereas 11 cases (74%) showed ≤10% cells with grooves. The sensitivity and specificity of nuclear grooves for PCT were 65% and 95%, respectively, at the level of ≥20%. While those at the level of ≤10% were 100% and 68%, respectively.

In a study by Jing and Michael[11] wherein they reviewed 22 cases which were cytologically diagnosed as PCT but did not correlate histologically, they found that occasional nuclear grooves were present in all the 22 cases. They were of the opinion that occasional nuclear grooves may lead to a false-positive diagnosis of PCT.


  Conclusion Top


To conclude, nuclear grooves can be seen in PCT as well as nonpapillary carcinoma cases including nonneoplastic lesions of thyroid. A false-positive diagnosis may be rendered by the presence of focal and occasional nuclear grooving, whereas a false-negative diagnosis may be a result of overlooking few nuclear grooves. Hence, this semiquantative approach may improve diagnostic accuracy. ≥20% cells with nuclear grooves are virtually diagnostic of PCT in our experience.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Amrikachi M, Ramzy I, Rubenfeld S, Wheeler TM. Accuracy of fine-needle aspiration of thyroid: A review of 6226 cases and correlation with surgical or clinical outcome. Arch Pathol Lab Med 2001;125:484-8.  Back to cited text no. 1
    
2.
DeMay RM. The Art and Science of Cytopathology. Chicago: ASCP Press; 1996. p. 703-78.  Back to cited text no. 2
    
3.
LiVolsi VA. Papillary neoplasms of the thyroid. Pathologic and prognostic features. Am J Clin Pathol 1992;97:426-34.  Back to cited text no. 3
    
4.
Scopa CD, Melachrinou M, Saradopoulou C, Merino MJ. The significance of the grooved nucleus in thyroid lesions. Mod Pathol 1993;6:691-4.  Back to cited text no. 4
    
5.
Chan JK, Saw D. The grooved nucleus. A useful diagnostic criterion of papillary carcinoma of the thyroid. Am J Surg Pathol 1986;10:672-9.  Back to cited text no. 5
    
6.
Rupp M, Ehya H. Nuclear grooves in the aspiration cytology of papillary carcinoma of the thyroid. Acta Cytol 1989;33:21-6.  Back to cited text no. 6
    
7.
Shurbaji MS, Gupta PK, Frost JK. Nuclear grooves: A useful criterion in the cytopathologic diagnosis of papillary thyroid carcinoma. Diagn Cytopathol 1988;4:91-4.  Back to cited text no. 7
    
8.
Bhambhani S, Kashyap V, Das DK. Nuclear grooves. Valuable diagnostic feature in may-grünwald-giemsa-stained fine needle aspirates of papillary carcinoma of the thyroid. Acta Cytol 1990;34:809-12.  Back to cited text no. 8
    
9.
Gould E, Watzak L, Chamizo W, Albores-Saavedra J. Nuclear grooves in cytologic preparations. A study of the utility of this feature in the diagnosis of papillary carcinoma. Acta Cytol 1989;33:16-20.  Back to cited text no. 9
    
10.
Yang YJ, Demirci SS. Evaluating the diagnostic significance of nuclear grooves in thyroid fine needle aspirates with a semiquantitative approach. Acta Cytol 2003;47:563-70.  Back to cited text no. 10
    
11.
Jing X, Michael CW. Potential pitfalls for false suspicion of papillary thyroid carcinoma: A cytohistologic review of 22 cases. Diagn Cytopathol 2012;40 Suppl 1:E74-9.  Back to cited text no. 11
    




 

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Abstract
Introduction
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