Questions about a risk of malignancy of toxic adenomas and the problems of their preoperative diagnosis

Background. The purpose was to study the cytomorphological structure of autonomously functioning thyroid nodules and the prevalence of cancer in this group based on a retrospective analysis of laboratory, instrumental and morphological data. Materials and methods. Patients with toxic adenoma (TA) were included in the study, who were treated in the V.P. Komisarenko Institute of Endocrinology and Metabolism of the National Academy of Medical Sciences of Ukraine (IEM) in 2010–2019. With the help of the medical information system TerDep from the clinical database of the IEM, patients with TA were selected who were operated at the Department of Endocrine Surgery in this period. There were 188 patients with thyroid TA, 156 (83 %) women and 32 (17 %) men. Their average age was 53.9 ± 1.2 years. To study the structural state of the thyroid, the results of ultrasound examination were analyzed, as well as cytological, immunocytochemical and morphological characteristics of TA. In patients with nodular/multinodular goiter, the size of formations was assessed, the data of cytological and immunocytochemical studies were analyzed. The prevalence of thyroid cancer among patients with TA was evaluated based on histological findings. Results. According to the ultrasound data, the sizes of TA ranged from 1.1 to 8.6 cm, with an average of 4.30 ± 0.09 cm. Echographic signs of nodular vascularization were recorded in 36 % of patients. Microcalcifications were observed in 9.4 % of cases. In all cases, the nodules had the correct shape, in 83.9 % — a clear contour, in 16.1 % — not clear contour. In 67.1 % of patients, the nodules were described as isoechogenic, in 32.9 %, a moderately reduced echogenicity of the nodules was noted. Fine needle aspiration biopsy with cytological examination was performed in 121 patients. In 88.5 % of cases, a cytological conclusion corresponded to Bethesda II (nodular goiter or adenomatous nodules), in 9.1 % — to Bethesda IV (follicular neoplasia), in 0.8 % — to Bethesda III (signs of epithelial atypia), in 0.8 % — to suspicion of malignancy (Bethesda V), and 0.8 % of patients had an uninformative cytological conclusion (Bethesda I). The frequency of detecting thyroid cancer among the total number of patients with TA was 3/188 (1.6 %). A detailed analysis of these cases showed that one patient had noninvasive encapsulated papillary carcinoma with oxyphil cell changes (cytological conclusion of follicular neoplasia with oxyphil cell metaplasia (Bethesda IV)), one had follicular carcinoma, and one had a tumor with uncertain malignant potential (cytological conclusion of adenomatous nodules (Bethesda II)). Conclusions. The sizes of the toxic adenoma ranged from 1.1 to 8.6 cm. The frequency of thyroid cancer among the total number of patients with TA was 1.6 %. The presence of hyperfunctioning thyroid TA cannot completely exclude the presence of malignancy. Complex ultrasounds studies with fine needle aspiration biopsy from different areas of nodules can be an adequate approach to rule out malignancy among toxic adenomas.