Abstract

The pathological classification of thyroid diseases have been changed time to time aiming to meet the more accurate and suitable prognosis as well as the treatment. In practice the choice of operation was neccessary or not in the best way of treatment for the patients. In oder to determine the type of thyroid diseases before or during operation, among many methods including the non-invasive (ultrasound, ultrasound elastography…), mini-invasive (core biopsy) or invasive ways (cryosection biopsy, surgery), fine needle aspiration (FNA) cytopathology combining with frozen section diagnosis in such cases still play the most reliable and applicable one in the world and Vietnam as well. Cytologically, in the world there are many classification systems for reporting thyroid cytopathology from the pathologists of UK Royal College, Australia, Italy and US in which the Bethesda (US) system has been applied in the majority of pathology practices in North America and in many European and Asian coutries. According to Bethesda, the thyroid gland diseases were divided as 6 groups with the malignant risks and the clinical management. Due to the changes in the WHO 2017 histopathology classification comparing with WHO 2004 one, the cytology classification of Bethesda 2017 had some changes, focusing on the malignant risk. Especially one malignant type of tumour before called Encapsulated Variant of Papillary Thyroid Carcinoma is reclassified as Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features. This helps reduce the overtreatment of indolent tumours for patient such as total thyroidectomy. The new histopathological classification of WHO in the year 2022 based on the previous one with some clarified and additional changes. The tumours were devided in to 3 main groups: benign, low – risk and malignant neoplasms, the papillary microcarcinoma should not be considered as a distinct subtype and the subtype of adenoma with papillary architectures including. The grade classification of malignant tumours were more detailed and standardized. Otherwise the Hurthle tumours should be renamed as oncocytic ones.