Study of Correlation of Cytomorphological Features of Lymphocytic Thyroiditis with Biochemical Parameters and Vitamin D Deficiency

Introduction: Fine Needle Aspiration Cytology (FNAC) of the thyroid is a reliable and common method used for diagnosis of chronic Lymphocytic Thyroiditis (LT) which is an autoimmune disease. Vitamin D (Vit D) deficiency, a prevalent health problem, is known to have correlation with various autoimmune diseases especially chronic LT. Aim: To evaluate the relationship between Vit D levels, biochemical parameters with cytomorphological features of LT. Materials and Methods: The present cohort study was conducted on 88 patients with cytological evidence of LT at a thyroid research centre in northern India between June 2017 to September 2018. Thyroid Stimulating Hormone (TSH), Antithyroid Peroxidase (ATPO) Antibody and Vit D levels along with patient’s clinical presentation, and thyroid ultrasound were evaluated for all subjects. The cytological grades and other cytomorphological features were correlated with these parameters. Results: Most of the patients were females (82, 93.2%) who presented with diffuse thyromegaly (69, 78.4%) and had hypothyroidism (58, 65.9%). By cytology grade I thyroiditis (40, 45.5%) was commonest followed by grade II (38, 43.2%). The Vit D deficiency and elevated ATPO were seen in 72 (81.8%) and 78 (88.6%) patients, respectively. Lowest level of Vit D (7.8±4.9 ng/mL) was seen in grade III patients. Significant correlation was observed between ATPO and Vit D levels with cytomorphological grades and some cytomorphological features like Hurthle cell change and plasma cells presence. While TSH levels correlated significantly with cytological grades only in hypothyroid group. Conclusion: This study found that Vit D deficiency and ATPO levels significantly correlates with cytological grades of thyroiditis and affect certain cytomorphological features like plasma cells presence, suggesting lower levels of Vit D and higher ATPO may be related to more active disease.