THE RELATIONSHIP BETWEEN THYROID STATUS, HASHIMOTO’S THYROIDITIS AND ULTRASOUND GUIDED THYROID FINE NEEDLE ASPIRATION BIOPSY RESULTS
Friday, May 8, 2020
11:30 AM – 11:45 AM
Participants should be aware of the following financial/non-financial relationships: Jaya Naran, DO: Disclosure information not submitted.
Objective : To assess the relationship between thyroid status, presence of Hashimoto’s thyroiditis, and ultrasound-guided thyroid fine needle aspiration biopsy (USGFNA) results.
Methods: Cytology results were retrospectively analyzed in patients who underwent USGFNA in our outpatient clinic from 2016 to 2019. Attending endocrinologists and fellows performed biopsies. Two to six passes were made for each nodule. USGFNA was performed with 23 or 25 gauge needle attached to 10 cc syringe. Each nodule was considered as its own case for data analysis. Cytology results were categorized as malignant, benign, indeterminate, and unsatisfactory. Unsatisfactory results were eliminated. Patients were categorized as euthyroid, hyperthyroid, and hypothyroid based on TSH results. There were 494 euthyroid, 49 hyperthyroid, and 19 hypothyroid nodules. Antibodies were available for 276 nodules and 60 were diagnosed with Hashimoto’s thyroiditis. USGFNA results were compared among categories with a chi-square test.
Results: 695 nodules were biopsied. 133 unsatisfactory results were eliminated. 290 nodules (52%) were from the right lobe, 244 (43%) from the left, and 28 (5%) from isthmus, with a total of 562 nodules. 251 biopsies were done on solitary nodules, 197 on 2 nodules, 94 on 3 nodules and 20 on 4 nodules on the same patient. The average diameter of the nodules was 22.1 ± 12 mm (average ± SD), with a minimum of 7 and a maximum of 90 mm. The median volume of nodules was 1.49 cm3. Amongst euthyroid nodules (n=494), 3% were malignant, 82% benign, and 15% indeterminate. Amongst hyperthyroid nodules (n=49), 4% were malignant, 88% benign, and 8% indeterminate. Amongst hypothyroid nodules (n=19), 16% were malignant, 74% benign, and 10% indeterminate. Thyroid status had a significant effect on USGFNA outcome where hypothyroid nodules were likely to be malignant (p=0.035). Amongst biopsies without Hashimoto’s thyroiditis (n=216), 4% were malignant, 83% benign, and 13% indeterminate. Amongst biopsies with Hashimoto’s thyroiditis (n=60), 2% were malignant, 80% benign, and 18% indeterminate. There was no statistical significance between Hashimoto’s thyroiditis and risk of malignancy (p=0.279).
Discussion/Conclusion: USGFNA showed significantly more malignant results in nodules with hypothyroidism compared to nodules with euthyroidism or hyperthyroidism. TSH has the ability to stimulate normal thyroid follicular cells as well as malignant thyroid cells. Elevated TSH levels, but not presence of elevated thyroid antibodies should be considered as predisposing risk factor for thyroid cancer.