Cytological Diagnosis of Hashimoto's Thyroiditis Revealing the Increased Frequency than Expected: A Retrospective Study of 750 Thyroid Aspirates

Background: Hashimoto’s thyroiditis (HT), an autoimmune disease is the commonest cause of hypothyroidism in iodine sufficient areas of the world. Fine needle aspiration cytology (FNAC) is the gold standard for the diagnosis of this condition. Aims: To assess the frequency of HT in total number of thyroid aspirates on the basis of cytomorphology and correlate it with clinical history, radiological findings, thyroid hormone status and antithyroid antibody titres wherever available. Material and methods: At a tertiary level teaching hospital in north India we retrospectively analysed 750 thyroid aspirates and found 58 HT in these on cytomorphology. Clinical findings, thyroid function and thyroid peroxidise (TPO) antibody profile were correlated with cytomorphological features. We further subdivided it in different age and sex groups to assess the frequency in all these groups. Results: Fine needle aspiration smears were satisfactory for evaluation in all cases with HT. frequency of HT was more than expected, 58 (7.73%) out of total 750 aspirates. Most patients with HT were women 50 (86.21%) and in 2 nd to 3 rd decades. Diffuse goitre was the commonest 41 (70.69%) presentation. Hypothyroidism was the commonest 35 (60.34%) feature. Anti TPO antibodies were elevated in 10/12 (83.33%) patients. Classical HT was seen in 40 (69%) and florid lymphocytic thyroiditis pattern in 18 (31%) patients. Conclusion: Hashimoto’s thyroiditis is more frequent than expected, especially in women of younger age groups.