Thyroid fine-needle aspiration and The Bethesda Classification System.

INTRODUCTION: Fine-needle aspiration (FNA) is a cornerstone in diagnosing thyroid nodules. For decades, Danish FNA has been categorised into the groups: "FNA not performed", "Inadequate", "Cystic", "Inconclusive", "Benign", "Suspicious", "Malignant" and "Information missing". Internationally, The Bethesda Classification System (TBCS) is increasingly accepted, especially owing to a detailed specification of FNA suspicious for malignancy. The Danish "Suspicious" group is very broad and includes atypia, follicular neoplasia and FNA suspicious of other malignancies. The purpose of this study was to apply TBCS to the Danish "Suspicious" FNA group and to estimate the frequency of malignancy in the individual Bethesda groups (BG). METHODS: This descriptive study is based on a prospective cohort from the THYKIR database. It includes 479 patients with a "Suspicious" FNA and surgical treatment in The Region of Southern Denmark from 2001 to 2013. Based on pathology records, FNA was classified according to the TBCS. Malignancy was determined by the histological diagnosis from the THYKIR database. RESULTS: The Danish "Suspicious" group was allocated to the BG I, II, III, IV, V and VI with a malignancy risk of 36.4%, 13.3%, 17.2%, 16.1%, 55.3% and 88.2%, respectively. CONCLUSIONS: The Danish "Suspicious" group contains a broad spectrum of BG with varying malignancy risk. The results indicate a need for standardisation of the Danish FNA classification. A national introduction of the TBCS might secure an international and comparable standard. FUNDING: none. TRIAL REGISTRATION: not relevant.

Risk of malignancy in fine-needle aspiration biopsy in patients with thyroid nodules.

INTRODUCTION: Fine-needle aspiration biopsy (FNAB) is the cornerstone of thyroid nodule evaluation. In most cases, FNAB can discriminate between benign and malignant disease. In other cases, it is only indicative of malignancy and the results are considered "suspicious". In Denmark, thyroid FNAB results are categorised into six groups: "inadequate", "cystic", "inconclusive", "benign", "suspicious" and "malignant". The risk of malignancy in the Danish "suspicious" group is of interest for patients as well as doctors participating in the diagnosis and treatment. The Danish Thyroid Surgery Database (THYKIR) registers preoperative thyroid FNAB and final histology. The aim of this study was to assess the malignancy risk among patients with a suspicious thyroid FNAB according to the Danish criteria and to identify possible predictors of malignant histology. METHODS: A prospective cohort counting 483 patients with a "suspicious" thyroid FNAB who had been treated surgically in The Region of Southern Denmark in the 2001-2013 period was retrieved from the THYKIR database. RESULTS: The risk of malignancy in the Danish thyroid FNAB "suspicious" group is 22%. Serum thyroid-stimulating hormone outside the normal range and vocal cord palsy may be patient-related predictors of malignancy. CONCLUSION: Awaiting the introduction of reliable tools for preoperative evaluation, the current practice with histo-logical clarification of the "suspicious" thyroid FNAB seems justified. FUNDING: none. TRIAL REGISTRATION: not relevant.