8229 Prevalence of Thyroid Cancer in Patients with Hashimotos Thyroiditis Presenting Concomitant Thyroid Nodular Disease

Abstract Disclosure: M.A. Alvarez Castillo: None. L. Sanchez Arriaga: None. A. Segovia Palomo: None. Introduction: Hashimoto's thyroiditis (HT) is the most frequent autoimmune thyroid disease and the main cause of goiter and hypothyroidism; it induces a process of aseptic autoimmune inflammation. Fibroinflammatory changes lead to the development of thyroid nodules (TN), additionally chronic inflammation is an important player in the development of cancer, although this association is controversial. The prevalence of thyroid cancer (TC) in patients with HT ranges from 0.61-58.4% (25.01%), being higher than in patients with TN without concomitant HT. Objective: To know the prevalence of malignancy in patients with HT who present thyroid nodular disease. Methodology: An observational, descriptive, retrospective, and longitudinal study was carried out. Patients with HT diagnosis were selected by measuring Ab TPO and/or Ab TG who presented an ultrasound diagnosis of TN and FNAB of the thyroid lesion had been performed. Descriptive statistics and linear regression were used. Results: 87 patients: 6 (6.9%) men and 81 (93.1%) women aged 47.9 (12.7) years. 4 (4.5%) required FNAB in 2 TN, for a total of 91 TN studied. 64% had a diagnosis of hypothyroidism and were taking LT4, TSH 4.40 (4.44) mUI/mL, FT4 1.00 (0.27) ng/dL. Mean Ab TPO was 794.7 ± 1354.6. Diagnosis time 19.5 (29.1) months. 39.6% the detection was made by the patient and 35.2% by the doctor. Major axis was 18.8 (12.1) mm. Ultrasound pattern of single TN 58.2% and multinodular 41.8%. Median TIRADS was 4, with a mode of 5. 81.3% reported Bethesda II and 18.7% malignant or suspected, were sent for surgery, malignancy was confirmed in 16/ 17 lesions. 14 (15.3%) were TPC and 2 lymphomas, the main subtypes were classic papillary and NHL, respectively. Mode of ATA risk was intermediate. Multivariate analysis only TIRADS represented risk factor (OR 2.08) Conclusions: The frequency of TC in our population was 15.3%, which reflects a higher prevalence of malignancy in thyroid nodules in patients with chronic thyroiditis, in accordance with what has been reported in other series. Presentation: 6/3/2024