Anti-TPO Antibodies in Euthyroid Neck Swelling Patients with Cytologically Proven Autoimmune Thyroiditis: A Cross-sectional study for Early Identification of Thyroid Failure.

Meenakshi Chaudhary; Sanjeev Narang; S. K. Nema; Neeraj Gour

doi:10.51168/jzvwcq05

Authors

Dr. Meenakshi Chaudhary Senior Resident, Department of Pathology, ESIC Hospital, Bhiwadi, Rajasthan, India
Dr. Sanjeev Narang Professor, Department of Pathology & Dean, Index Medical College, Hospital & Research Centre, Indore, Madhya Pradesh, India
Dr. Srikant Nema Professor, Director of Pathology and Director of Post-Graduate Academics, Amaltas Institute of Medical Science, Dewas, Madhya Pradesh, India
Dr. Neeraj Gour Professor, Department of Community Medicine, SHKM Government Medical College, Nalhar, Haryana, India

DOI:

https://doi.org/10.51168/jzvwcq05

Keywords:

Autoimmune thyroiditis, anti-thyroid peroxidase antibody, euthyroid, Hashimoto's thyroiditis, lymphocytic thyroiditis, subclinical hypothyroidism

Abstract

Background: Autoimmune thyroiditis, including Hashimoto's and lymphocytic thyroiditis, may be cytologically evident on fine-needle aspiration cytology (FNAC) before biochemical thyroid dysfunction develops. Anti-thyroid peroxidase (anti-TPO) antibodies may identify euthyroid patients with underlying thyroid autoimmunity who require follow-up.

Objectives: To determine the frequency of euthyroidism among cytologically proven autoimmune thyroiditis cases and characterize their anti-TPO antibody profile.

Methods: In this hospital-based, cross-sectional study of 100 satisfactorily aspirated thyroid FNAC cases conducted over 18 months (February 2019–August 2020), autoimmune thyroiditis (Hashimoto's and lymphocytic thyroiditis) was diagnosed in 18 cases; granulomatous thyroiditis (n=3), being of non-autoimmune (post-viral) aetiology, was analysed separately as a comparator. appropriate statistical tests were applied wherever necessary.

Results: Of the 18 autoimmune thyroiditis cases, one-third (6, 33.3%) were euthyroid at presentation, while 6 (33.3%) were hyperthyroid and 6 (33.3%) hypothyroid. A detectable anti-TPO titre (>9 IU/L) was present in 19 of 21 thyroiditis cases (90.5%); across the cohort, 22 of 41 patients with a detectable titre (53.7%) were euthyroid, indicating antibody elevation often precedes biochemical dysfunction. Mean anti-TPO titre was markedly higher in Hashimoto's (813.36±487.51 IU/L) and lymphocytic thyroiditis (252.81±228.30 IU/L) than granulomatous thyroiditis (31.87±55.21 IU/L; one-way ANOVA, F=7.21, p=0.005). Detectable anti-TPO was significantly more frequent in thyroiditis than non-thyroiditis lesions (90.5% vs 27.8%; χ²=24.37, p<0.001; odds ratio 24.6).

Conclusion: A substantial proportion of patients with cytologically proven autoimmune thyroiditis remain biochemically euthyroid at diagnosis; anti-TPO positivity is more frequent among euthyroid than dysfunctional patients, identifying a group at increased future risk of hypothyroidism.

Recommendation: Anti-TPO estimation is recommended as a routine adjunct to FNAC in cytologically diagnosed autoimmune thyroiditis, irrespective of thyroid-function status, with periodic follow-up of antibody-positive euthyroid patients to enable early detection of progression to hypothyroidism.

Author Biographies

Dr. Meenakshi Chaudhary, Senior Resident, Department of Pathology, ESIC Hospital, Bhiwadi, Rajasthan, India

is a Senior Resident in the Department of Pathology, ESIC Hospital, Bhiwadi, Rajasthan, India, with a research interest in thyroid cytopathology and cytology–serology correlation.
Dr. Sanjeev Narang, Professor, Department of Pathology & Dean, Index Medical College, Hospital & Research Centre, Indore, Madhya Pradesh, India

is Professor of Pathology and Dean, Index Medical College, Hospital and Research Centre, Indore, India.
Dr. Srikant Nema, Professor, Director of Pathology and Director of Post-Graduate Academics, Amaltas Institute of Medical Science, Dewas, Madhya Pradesh, India

is Professor and Director of Pathology, and Director of Post-Graduate Academics, Amaltas Institute of Medical Science, Dewas, India.
Dr. Neeraj Gour, Professor, Department of Community Medicine, SHKM Government Medical College, Nalhar, Haryana, India

is Professor in the Department of Community Medicine, SHKM Government Medical College, Nalhar, Haryana, India, with an interest in biostatistics and epidemiological methodology.

References

1. Vanderpump MP, Tunbridge WM, French JM, Appleton D, Bates D, Clark F, et al. The incidence of thyroid disorders in the community: a twenty-year follow-up of the Whickham Survey. Clin Endocrinol (Oxf). 1995;43(1):55-68.

https://doi.org/10.1111/j.1365-2265.1995.tb01894.x

2. Cibas ES, Ali SZ. The 2017 Bethesda System for Reporting Thyroid Cytopathology. Thyroid. 2017;27(11):1341-6.

https://doi.org/10.1089/thy.2017.0500

3. Jayaram G, Marwaha RK, Gupta RK, Sharma SK. Cytomorphologic aspects of thyroiditis. A study of 51 cases with functional, immunologic and ultrasonographic data. Acta Cytol. 1987;31(6):687-93.

4. von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP; STROBE Initiative. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. Lancet. 2007;370(9596):1453-7.

https://doi.org/10.1016/S0140-6736(07)61602-X

5. Jayaram G. Thyroid. In: Orell SR, Sterrett GF, editors. Fine Needle Aspiration Cytology. 5th ed. Gurgaon: Reed Elsevier India; 2012. p. 118-55.

https://doi.org/10.1016/B978-0-7020-3151-9.00006-2

6. Engler H, Riesen WF, Keller B. Anti-thyroid peroxidase (anti-TPO) antibodies in thyroid diseases, non-thyroidal illness and controls. Clinical validity of a new commercial method for detection of anti-TPO (thyroid microsomal) autoantibodies. Clin Chim Acta. 1994;225(2):123-36.

https://doi.org/10.1016/0009-8981(94)90040-X

7. Hoogendoorn EH, Hermus AR, de Vegt F, Ross HA, Verbeek AL, Kiemeney LA, et al. Thyroid function and prevalence of anti-thyroperoxidase antibodies in a population with borderline sufficient iodine intake: influences of age and sex. Clin Chem. 2006;52(1):104-11.

https://doi.org/10.1373/clinchem.2005.055194

8. Rho MH, Kim DW, Hong HP, Park YM, Kwon MJ, Jung SJ, et al. Diagnostic value of antithyroid peroxidase antibody for incidental autoimmune thyroiditis based on histopathologic results. Endocrine. 2012;42(3):647-52.

https://doi.org/10.1007/s12020-012-9695-y

9. Bromińska B, Bromiński G, Owecki M, Ruchała M. Anti-thyroidal peroxidase antibodies are associated with thyrotropin levels in hypothyroid patients and in euthyroid individuals. Ann Agric Environ Med. 2017;24(3):431-4.

https://doi.org/10.5604/12321966.1232090

10. Kumar N, Ray C, Jain S. Aspiration cytology of Hashimoto's thyroiditis in an endemic area. Cytopathology. 2002;13(1):31-9.

https://doi.org/10.1046/j.1365-2303.2002.00366.x

11. Singh N, Kumar S, Negi VS, Siddaraju N. Cytomorphologic study of Hashimoto's thyroiditis and its serologic correlation: a study of 150 cases. Acta Cytol. 2009;53(5):507-16.

https://doi.org/10.1159/000325377

12. Bhatia A, Rajwanshi A, Dash RJ, Mittal BR, Saxena AK. Lymphocytic thyroiditis - is cytological grading significant? A correlation of grades with clinical, biochemical, ultrasonographic and radionuclide parameters. CytoJournal. 2007;4:10.

https://doi.org/10.1186/1742-6413-4-10