Endocrine Abstracts

Introduction: Thyroid nodules are very common and elucidating the nature of these thyroid nodules is an important task.

Methodology: Patients who had an ultrasound guided fine needle aspiration (FNA) of a thyroid nodule between January 2008 and June 2012 were retrospectively audited and their ultrasonographic and biochemical characteristics where analysed. For those patients who were operated nodule characteristics were correlated with thyroid histology.

Results: 397 thyroid aspirates were identified. Using The Betsheda System for Reporting Thyroid Cytopathology (TBSRTC) 59.5% were classified as category II (benign), 15.4% category IV (follicular) 4.8% category V (suspicious for malignancy) and 8.4% category VI (malignant).

Statistical analysis of operated patients (n=97) yielded a positive predictive value for malignancy (for those who were classified according to TBSRTC categories V and VI) of 89.5%, a negative predictive value of 86.4%, sensitivity of 81.0% and specificity of 92.7%.

42 patients who were operated had thyroid malignancy, of whom 41 had a papillary carcinoma and 1 patient had a medullary thyroid carcinoma. The mean age at presentation was 48.0 years (S.D.±12.6 years), the mean largest diameter of the papillary carcinomas was 13.8 mm (S.D.±8.6 mm) and 48.8% had lymph node involvement. 58.5% of patients with malignant histology had more than 1 focus of malignancy in the thyroid. The mean size of thyroid nodule on ultrasound of these patients was 17.5 mm (S.D.±9.4 mm), 53.7% had a hypoechoic nodule and 48.8% had microcalcifications. These findings differed from those who had a follicular adenoma on histology, where 13.0% had a hypoechoic nodule on ultrasound and 16.1% had microcalcifications.

Conclusions: These findings further establish that FNA of thyroid nodules is a very important and helpful tool in the management of thyroid nodules. Important characteristics of thyroid cancer are shown including the high rate of multifocality seen in our patient cohort.