Relationship between Serum Thyrotropin (TSH) and Cytology Findings of Thyroid Nodules

Thyroid cancer is the most common malignancy of the endocrine. The factors involved in differentiation of thyroid nodules are highly important. This study was done to determine the relationship between serum TSH and cytology finding of thyroid nodules. In this cross-sectional study, 275 patients enrolled. Complete physical examination was done and the serum TSH was measured by IRMA method. The serum T4 and T3 were also measured if the TSH was outside the normal range. In all patients thyroid ultrasound was performed. Fine Needle Aspiration (FNA) biopsy was done on all thyroid nodules and cytology results were interpreted by a pathologist. Data was then analyzed applying Stata software. The mean age of the patients was 42.5±12.5 years and there were 85.8% female. The mean of BMI was 23.7±2.2 kg/m2. Calcification was found in 36% of thyroid nodules and microcalcification was observed in 92%. The mean TSH level in patients with malignancy was higher than that of those with benign thyroid nodules. Each unit increase in levels of TSH increased the risk of thyroid malignancy by 23% (OR=1.23; CI: 1.01-1.5). This risk has also increased by 38% with each unit increase in BMI (OR= 1.38; CI: 1.15- 1.66). This study suggests that serum TSH level could be used as a predictor of the probability of malignancy in thyroid nodules.