The article discusses the diagnostic capabilities of fine-needle aspiration biopsy (FNA) for the detection of malignant tumors of the thyroid gland. A central place in diagnosis is occupied by fine-needle aspiration biopsy, the results of which were the basis for the selection of patients subject to surgical treatment. The results of FNA, indicating the presence of carcinoma or the impossibility of excluding its presence, served as the basis for surgical intervention for the patient .